diff --git a/api/kv.go b/api/kv.go
index ba74057fcc..c1a8923bef 100644
--- a/api/kv.go
+++ b/api/kv.go
@@ -168,6 +168,10 @@ func (k *KV) Release(p *KVPair, q *WriteOptions) (bool, *WriteMeta, error) {
 }
 
 func (k *KV) put(key string, params map[string]string, body []byte, q *WriteOptions) (bool, *WriteMeta, error) {
+	if len(key) > 0 && key[0] == '/' {
+		return false, nil, fmt.Errorf("Invalid key. Key must not begin with a '/': %s", key)
+	}
+
 	r := k.c.newRequest("PUT", "/v1/kv/"+key)
 	r.setWriteOptions(q)
 	for param, val := range params {
diff --git a/api/kv_test.go b/api/kv_test.go
index 8f2b54945d..b4dcbf5766 100644
--- a/api/kv_test.go
+++ b/api/kv_test.go
@@ -30,6 +30,14 @@ func TestClientPutGetDelete(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
+	// Put a key that begins with a '/'
+	invalidKey := "/test"
+	value = []byte(invalidKey)
+	p = &KVPair{Key: key, Flags: 42, Value: value}
+	if _, err := kv.Put(p, nil); err == nil {
+		t.Fatalf("Invalid key not detected: %s", invalidKey)
+	}
+
 	// Get should work
 	pair, meta, err := kv.Get(key, nil)
 	if err != nil {