diff --git a/src/core.cpp b/src/core.cpp
index 48d5c7401..36a623973 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -713,17 +713,23 @@ void Core::acceptFriendRequest(const QString& userId)
 
 void Core::requestFriendship(const QString& friendAddress, const QString& message)
 {
-    qDebug() << "Core: requesting friendship of "+friendAddress;
-    CString cMessage(message);
-
-    int friendId = tox_add_friend(tox, CFriendAddress(friendAddress).data(), cMessage.data(), cMessage.size());
     const QString userId = friendAddress.mid(0, TOX_CLIENT_ID_SIZE * 2);
-    if (friendId < 0) {
-        emit failedToAddFriend(userId);
-    } else {
-        // Update our friendAddresses
-        Settings::getInstance().updateFriendAdress(friendAddress);
-        emit friendAdded(friendId, userId);
+
+    if(hasFriendWithAddress(friendAddress)) {
+        emit failedToAddFriend(userId, "Friend is already added");
+    }
+    else {
+        qDebug() << "Core: requesting friendship of "+friendAddress;
+        CString cMessage(message);
+
+        int friendId = tox_add_friend(tox, CFriendAddress(friendAddress).data(), cMessage.data(), cMessage.size());
+        if (friendId < 0) {
+            emit failedToAddFriend(userId);
+        } else {
+            // Update our friendAddresses
+            Settings::getInstance().updateFriendAdress(friendAddress);
+            emit friendAdded(friendId, userId);
+        }
     }
     saveConfiguration();
 }
@@ -1592,6 +1598,46 @@ void Core::createGroup()
     emit emptyGroupCreated(tox_add_groupchat(tox));
 }
 
+bool Core::hasFriendWithAddress(const QString &addr) const
+{
+    // Valid length check
+    if(addr.length() != (TOX_FRIEND_ADDRESS_SIZE * 2)) {
+        return false;
+    }
+
+    QString pubkey = addr.left(TOX_CLIENT_ID_SIZE * 2);
+    return hasFriendWithPublicKey(pubkey);
+}
+
+bool Core::hasFriendWithPublicKey(const QString &pubkey) const
+{
+    // Valid length check
+    if(pubkey.length() != (TOX_CLIENT_ID_SIZE * 2)) {
+        return false;
+    }
+
+    bool found = false;
+    const uint32_t friendCount = tox_count_friendlist(tox);
+    if (friendCount > 0) {
+        int32_t *ids = new int32_t[friendCount];
+        tox_get_friendlist(tox, ids, friendCount);
+        for (int32_t i = 0; i < static_cast<int32_t>(friendCount); ++i) {
+            // getFriendAddress may return either id (public key) or address
+            QString addrOrId = getFriendAddress(ids[i]);
+
+            // Set true if found
+            if(addrOrId.toUpper().startsWith(pubkey.toUpper())) {
+                found = true;
+                break;
+            }
+        }
+
+        delete[] ids;
+    }
+
+    return found;
+}
+
 QString Core::getFriendAddress(int friendNumber) const
 {
     // If we don't know the full address of the client, return just the id, otherwise get the full address
diff --git a/src/core.h b/src/core.h
index 2ad0f7ad7..1c439025a 100644
--- a/src/core.h
+++ b/src/core.h
@@ -53,6 +53,8 @@ public:
     QList<QString> getGroupPeerNames(int groupId) const; ///< Get the names of the peers of a group
     QString getFriendAddress(int friendNumber) const; ///< Get the full address if known, or Tox ID of a friend
     QString getFriendUsername(int friendNumber) const; ///< Get the username of a friend
+    bool hasFriendWithAddress(const QString &addr) const; ///< Check if we have a friend by address
+    bool hasFriendWithPublicKey(const QString &pubkey) const; ///< Check if we have a friend by public key
     int joinGroupchat(int32_t friendNumber, const uint8_t* pubkey,uint16_t length) const; ///< Accept a groupchat invite
     void quitGroupChat(int groupId) const; ///< Quit a groupchat
 
@@ -154,7 +156,7 @@ signals:
     void groupSentResult(int groupId, const QString& message, int result);
     void actionSentResult(int friendId, const QString& action, int success);
 
-    void failedToAddFriend(const QString& userId);
+    void failedToAddFriend(const QString& userId, const QString& errorInfo = QString());
     void failedToRemoveFriend(int friendId);
     void failedToSetUsername(const QString& username);
     void failedToSetStatusMessage(const QString& message);
diff --git a/src/widget/widget.cpp b/src/widget/widget.cpp
index 6494adad3..369c01b61 100644
--- a/src/widget/widget.cpp
+++ b/src/widget/widget.cpp
@@ -644,9 +644,14 @@ void Widget::addFriend(int friendId, const QString &userId)
     }
 }
 
-void Widget::addFriendFailed(const QString&)
+void Widget::addFriendFailed(const QString&, const QString& errorInfo)
 {
-    QMessageBox::critical(0,"Error","Couldn't request friendship");
+    QString info = QString("Couldn't request friendship");
+    if(!errorInfo.isEmpty()) {
+        info = info + (QString(": ") + errorInfo);
+    }
+
+    QMessageBox::critical(0,"Error",info);
 }
 
 void Widget::onFriendStatusChanged(int friendId, Status status)
diff --git a/src/widget/widget.h b/src/widget/widget.h
index 2193fee55..d5a8b27ad 100644
--- a/src/widget/widget.h
+++ b/src/widget/widget.h
@@ -101,7 +101,7 @@ private slots:
     void setUsername(const QString& username);
     void setStatusMessage(const QString &statusMessage);
     void addFriend(int friendId, const QString& userId);
-    void addFriendFailed(const QString& userId);
+    void addFriendFailed(const QString& userId, const QString& errorInfo = QString());
     void onFriendStatusChanged(int friendId, Status status);
     void onFriendStatusMessageChanged(int friendId, const QString& message);
     void onFriendUsernameChanged(int friendId, const QString& username);