B757-200
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem
Human Factors
Departed ZZZ and 30 min later we were notified via ACARS that there was Hazmat cargo on board that was not documented while we were on the ground. We were presented with incorrect paperwork and had no way of knowing about or capturing the error. Event was caused due to incorrect procedures by ramp personnel.
After departure notified via ACARS by Dispatch that the ramp failed to list 79.6 kg of dry ice in position 1 on the Dangerous Goods paperwork.  Paperwork provided by ramp prior to departure stated 'NO DG ON BOARD'. Error by ramp personnel.
Air Carrier flight crew and Dispatcher reported being notified of unmanifested Hazmat cargo after departure.