The present invention discloses a system and method for monitoring customer service agents' performance according to the interaction with one or more customers in a call center. The system comprises a call control server, a management console, and an agent console. The management console sends the call control server a first request, carrying a predetermined tag, to initiate a monitoring session, thereby triggering the call control server to send the agent console a second request, carrying the predetermined tag, to establish the monitoring session with the management console without notifying the agent, wherein during the monitoring session the agent console forwards a copy of data streams, related to the activities of the agent and one or more customer, to the management console.