diff --git a/src/DownloadEngineFactory.cc b/src/DownloadEngineFactory.cc
index 5bd8d53d..9fd1db42 100644
--- a/src/DownloadEngineFactory.cc
+++ b/src/DownloadEngineFactory.cc
@@ -52,6 +52,7 @@
 #include "AutoSaveCommand.h"
 #include "HaveEraseCommand.h"
 #include "TimedHaltCommand.h"
+#include "WatchProcessCommand.h"
 #include "DownloadResult.h"
 #include "ServerStatMan.h"
 #include "a2io.h"
@@ -163,6 +164,10 @@ DownloadEngineFactory::newDownloadEngine
                                                 stopSec));
     }
   }
+  if(op->defined(PREF_STOP_WITH_PROCESS)) {
+    unsigned int pid = op->getAsInt(PREF_STOP_WITH_PROCESS);
+    e->addRoutineCommand(new WatchProcessCommand(e->newCUID(), e.get(), pid));
+  }
   if(op->getAsBool(PREF_ENABLE_RPC)) {
     bool ok = false;
     static int families[] = { AF_INET, AF_INET6 };
diff --git a/src/Makefile.am b/src/Makefile.am
index 5d87e1ca..9a0e1493 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -223,7 +223,8 @@ SRCS =  Socket.h\
 	NullHandle.h\
 	a2iterator.h\
 	paramed_string.cc paramed_string.h\
-	rpc_helper.cc rpc_helper.h
+	rpc_helper.cc rpc_helper.h\
+	WatchProcessCommand.cc WatchProcessCommand.h
 
 if MINGW_BUILD
 SRCS += WinConsoleFile.cc WinConsoleFile.h
diff --git a/src/OptionHandlerFactory.cc b/src/OptionHandlerFactory.cc
index 65277520..c784d58d 100644
--- a/src/OptionHandlerFactory.cc
+++ b/src/OptionHandlerFactory.cc
@@ -673,6 +673,15 @@ OptionHandlerFactory::createOptionHandlers()
     op->addTag(TAG_ADVANCED);
     handlers.push_back(op);
   }
+  {
+    SharedHandle<OptionHandler> op(new NumberOptionHandler
+                                   (PREF_STOP_WITH_PROCESS,
+                                    TEXT_STOP_WITH_PROCESS,
+                                    NO_DEFAULT_VALUE,
+                                    0));
+    op->addTag(TAG_ADVANCED);
+    handlers.push_back(op);
+  }
   {
     SharedHandle<OptionHandler> op(new NumberOptionHandler
                                    (PREF_SUMMARY_INTERVAL,
diff --git a/src/WatchProcessCommand.cc b/src/WatchProcessCommand.cc
new file mode 100644
index 00000000..b68c5ef7
--- /dev/null
+++ b/src/WatchProcessCommand.cc
@@ -0,0 +1,132 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2011 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+/*
+ * Copyright 2011 Emmanuel Engelhart <kelson@kiwix.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU  General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+#include "WatchProcessCommand.h"
+#include "DownloadEngine.h"
+#include "RequestGroupMan.h"
+#include "LogFactory.h"
+#include "Logger.h"
+#include "fmt.h"
+
+#ifdef __APPLE__
+#import <sys/types.h>
+#import <sys/sysctl.h>
+#define MIBSIZE 4
+#endif
+
+namespace aria2 {
+
+WatchProcessCommand::WatchProcessCommand
+(cuid_t cuid,
+ DownloadEngine* e,
+ unsigned int pid,
+ bool forceHalt)
+  : TimeBasedCommand(cuid, e, 1, true),
+    pid_(pid),
+    forceHalt_(forceHalt)
+{}
+
+
+void WatchProcessCommand::preProcess()
+{
+  if(getDownloadEngine()->getRequestGroupMan()->downloadFinished() ||
+     getDownloadEngine()->isHaltRequested()) {
+    enableExit();
+  }
+}
+
+void WatchProcessCommand::process()
+{
+  // Check process pid_ is running. If it is not running, shutdown
+  // aria2.
+  A2_LOG_DEBUG(fmt("Checking proess %u", pid_));
+  bool waiting = true;
+#ifdef _WIN32
+  HANDLE process = OpenProcess(SYNCHRONIZE, FALSE, pid_);
+  DWORD ret = WaitForSingleObject(process, 0);
+  CloseHandle(process);
+  if (ret != WAIT_TIMEOUT) {
+    waiting = false;
+  }
+#elif __APPLE__
+  int mib[MIBSIZE];
+  struct kinfo_proc kp;
+  size_t len = sizeof(kp);
+
+  mib[0]=CTL_KERN;
+  mib[1]=KERN_PROC;
+  mib[2]=KERN_PROC_PID;
+  mib[3]=pid_;
+
+  int ret = sysctl(mib, MIBSIZE, &kp, &len, NULL, 0);
+  if (ret == -1 || len <= 0) {
+    waiting = false;
+  }
+#else
+  if (access(fmt("/proc/%u", pid_).c_str(), F_OK) == -1) {
+    waiting = false;
+  }
+#endif
+  if(!waiting) {
+    A2_LOG_INFO
+      (fmt("CUID#%lld - Process %u is not running. Commencing shutdown.",
+           getCuid(), pid_));
+    if(forceHalt_) {
+      getDownloadEngine()->requestForceHalt();
+    } else {
+      getDownloadEngine()->requestHalt();
+    }
+    enableExit();
+  }
+}
+
+} // namespace aria2
diff --git a/src/WatchProcessCommand.h b/src/WatchProcessCommand.h
new file mode 100644
index 00000000..e03833c4
--- /dev/null
+++ b/src/WatchProcessCommand.h
@@ -0,0 +1,62 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2011 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef D_WATCH_PROCESS_COMMAND_H
+#define D_WATCH_PROCESS_COMMAND_H
+
+#include "TimeBasedCommand.h"
+
+namespace aria2 {
+
+class DownloadEngine;
+
+class WatchProcessCommand:public TimeBasedCommand {
+public:
+  WatchProcessCommand
+  (cuid_t cuid,
+   DownloadEngine* e,
+   unsigned int pid,
+   bool forceHalt = false);
+
+  virtual void preProcess();
+
+  virtual void process();
+private:
+  unsigned int pid_;
+  bool forceHalt_;
+};
+
+} // namespace aria2
+
+#endif // D_WATCH_PROCESS_COMMAND_H
diff --git a/src/prefs.cc b/src/prefs.cc
index a8a95cc2..d2c2ad0b 100644
--- a/src/prefs.cc
+++ b/src/prefs.cc
@@ -321,6 +321,8 @@ const Pref* PREF_DOWNLOAD_RESULT = makePref("download-result");
 const Pref* PREF_HASH_CHECK_ONLY = makePref("hash-check-only");
 // values: hashType=digest
 const Pref* PREF_CHECKSUM = makePref("checksum");
+// value: pid
+const Pref* PREF_STOP_WITH_PROCESS = makePref("stop-with-process");
 
 /**
  * FTP related preferences
diff --git a/src/prefs.h b/src/prefs.h
index 562d89f0..e6d24635 100644
--- a/src/prefs.h
+++ b/src/prefs.h
@@ -276,6 +276,8 @@ extern const Pref* PREF_FTP_PASV;
 extern const Pref* PREF_FTP_REUSE_CONNECTION;
 // values: hashType=digest
 extern const Pref* PREF_CHECKSUM;
+// value: pid
+extern const Pref* PREF_STOP_WITH_PROCESS;
 
 /**
  * HTTP related preferences
diff --git a/src/usage_text.h b/src/usage_text.h
index 5c17c2fa..28b144d3 100644
--- a/src/usage_text.h
+++ b/src/usage_text.h
@@ -852,3 +852,10 @@
     "                              option will be ignored in BitTorrent downloads.\n" \
     "                              It will be also ignored if Metalink file\n" \
     "                              contains piece hashes.")
+#define TEXT_STOP_WITH_PROCESS                                          \
+  _(" --stop-with-process=PID      Stop application when process PID is not running.\n" \
+    "                              This is useful if aria2 process is forked from a\n" \
+    "                              parent process. The parent process can fork aria2\n" \
+    "                              with its own pid and when parent process exits\n" \
+    "                              for some reason, aria2 can detect it and shutdown\n" \
+    "                              itself.")