The US Navy hospital ship USNS Comfort played an integral role in the initial phases of Operation Unified Response-Haiti following the devastating earthquake that struck near Port-Au-Prince, Haiti, on January 12, 2010. Deployed to Haiti from its home in Baltimore, Maryland, just 4 days after the earthquake, the USNS Comfort would become the region's primary tertiary casualty receiving center for 6 weeks. The pathology and laboratory department staff onboard the ship helped support the mission and experienced unique mass casualty/disaster relief scenarios while underway. This article reviews the accounts of the core laboratory, microbiology, anatomic pathology, and blood bank divisions on the USNS Comfort from the chaotic first few weeks to the final patient discharge 40 days after Operation Unified Response-Haiti began.