diff --git a/src/kademlia/dht/DHT.java b/src/kademlia/dht/DHT.java
index e5f194c..ae631e1 100644
--- a/src/kademlia/dht/DHT.java
+++ b/src/kademlia/dht/DHT.java
@@ -80,7 +80,7 @@ public class DHT
      *
      * @throws java.io.IOException
      */
-    public boolean store(StorageEntry content) throws IOException
+    public synchronized boolean store(StorageEntry content) throws IOException
     {
         /* Lets check if we have this content and it's the updated version */
         if (this.entriesManager.contains(content.getContentMetadata()))
@@ -142,7 +142,7 @@ public class DHT
 
     }
 
-    public boolean store(KadContent content) throws IOException
+    public synchronized boolean store(KadContent content) throws IOException
     {
         return this.store(new StorageEntry(content));
     }
diff --git a/src/kademlia/dht/StoredContentManager.java b/src/kademlia/dht/StoredContentManager.java
index 3d541a5..5eee9bb 100644
--- a/src/kademlia/dht/StoredContentManager.java
+++ b/src/kademlia/dht/StoredContentManager.java
@@ -69,7 +69,7 @@ class StoredContentManager
      *
      * @return boolean
      */
-    public boolean contains(GetParameter param)
+    public synchronized boolean contains(GetParameter param)
     {
         if (this.entries.containsKey(param.getKey()))
         {
@@ -93,7 +93,7 @@ class StoredContentManager
     /**
      * Check if a content exist in the DHT
      */
-    public boolean contains(KadContent content)
+    public synchronized boolean contains(KadContent content)
     {
         return this.contains(new GetParameter(content));
     }
@@ -101,7 +101,7 @@ class StoredContentManager
     /**
      * Check if a StorageEntry exist on this DHT
      */
-    public boolean contains(StorageEntryMetadata entry)
+    public synchronized boolean contains(StorageEntryMetadata entry)
     {
         return this.contains(new GetParameter(entry));
     }