diff --git a/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CSRBuilder.java b/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CSRBuilder.java
index f15118bd..a320b96a 100644
--- a/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CSRBuilder.java
+++ b/acme4j-utils/src/main/java/org/shredzone/acme4j/util/CSRBuilder.java
@@ -16,6 +16,8 @@ package org.shredzone.acme4j.util;
 import java.io.IOException;
 import java.io.Writer;
 import java.security.KeyPair;
+import java.security.PrivateKey;
+import java.security.interfaces.ECKey;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -46,6 +48,7 @@ import org.bouncycastle.util.io.pem.PemWriter;
  */
 public class CSRBuilder {
     private static final String SIGNATURE_ALG = "SHA256withRSA";
+    private static final String EC_SIGNATURE_ALG = "SHA256withECDSA";
 
     private final X500NameBuilder namebuilder = new X500NameBuilder(X500Name.getDefaultStyle());
     private final List<String> namelist = new ArrayList<>();
@@ -156,8 +159,10 @@ public class CSRBuilder {
             extensionsGenerator.addExtension(Extension.subjectAlternativeName, false, subjectAltName);
             p10Builder.addAttribute(PKCSObjectIdentifiers.pkcs_9_at_extensionRequest, extensionsGenerator.generate());
 
-            JcaContentSignerBuilder csBuilder = new JcaContentSignerBuilder(SIGNATURE_ALG);
-            ContentSigner signer = csBuilder.build(keypair.getPrivate());
+            PrivateKey pk = keypair.getPrivate();
+            JcaContentSignerBuilder csBuilder = new JcaContentSignerBuilder(
+                            pk instanceof ECKey ? EC_SIGNATURE_ALG : SIGNATURE_ALG);
+            ContentSigner signer = csBuilder.build(pk);
 
             csr = p10Builder.build(signer);
         } catch (OperatorCreationException ex) {
diff --git a/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CSRBuilderTest.java b/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CSRBuilderTest.java
index 90e76819..6b432042 100644
--- a/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CSRBuilderTest.java
+++ b/acme4j-utils/src/test/java/org/shredzone/acme4j/util/CSRBuilderTest.java
@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.security.KeyPair;
+import java.security.Security;
 import java.util.Arrays;
 
 import org.bouncycastle.asn1.ASN1Encodable;
@@ -33,6 +34,7 @@ import org.bouncycastle.asn1.x509.Extension;
 import org.bouncycastle.asn1.x509.Extensions;
 import org.bouncycastle.asn1.x509.GeneralName;
 import org.bouncycastle.asn1.x509.GeneralNames;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.bouncycastle.openssl.PEMException;
 import org.bouncycastle.openssl.PEMParser;
 import org.bouncycastle.pkcs.PKCS10CertificationRequest;
@@ -51,10 +53,14 @@ import com.jcabi.matchers.RegexMatchers;
 public class CSRBuilderTest {
 
     private static KeyPair testKey;
+    private static KeyPair testEcKey;
 
     @BeforeClass
     public static void setup() {
+        Security.addProvider(new BouncyCastleProvider());
+
         testKey = KeyPairUtils.createKeyPair(512);
+        testEcKey = KeyPairUtils.createECKeyPair("secp256r1");
     }
 
     /**
@@ -88,6 +94,37 @@ public class CSRBuilderTest {
         writerTest(builder);
     }
 
+    /**
+     * Test if the generated CSR is plausible using a ECDSA key.
+     */
+    @Test
+    public void testECCGenerate() throws IOException {
+        CSRBuilder builder = new CSRBuilder();
+        builder.addDomain("abc.de");
+        builder.addDomain("fg.hi");
+        builder.addDomains("jklm.no", "pqr.st");
+        builder.addDomains(Arrays.asList("uv.wx", "y.z"));
+
+        builder.setCountry("XX");
+        builder.setLocality("Testville");
+        builder.setOrganization("Testing Co");
+        builder.setOrganizationalUnit("Testunit");
+        builder.setState("ABC");
+
+        assertThat(builder.toString(), is("CN=abc.de,C=XX,L=Testville,O=Testing Co,"
+                        + "OU=Testunit,ST=ABC,"
+                        + "DNS=abc.de,DNS=fg.hi,DNS=jklm.no,DNS=pqr.st,DNS=uv.wx,DNS=y.z"));
+
+        builder.sign(testEcKey);
+
+        PKCS10CertificationRequest csr = builder.getCSR();
+        assertThat(csr, is(notNullValue()));
+        assertThat(csr.getEncoded(), is(equalTo(builder.getEncoded())));
+
+        csrTest(csr);
+        writerTest(builder);
+    }
+
     /**
      * Checks if the CSR contains the right parameters.
      * <p>