The number of granulocytic stem cells (CFU-C) was measured in the peripheral blood of surviving and nonsurviving burned humans. It has been shown that the number of CFU-C in the peripheral blood of survivors increases over time and is elevated compared to the number found in normal humans. The number found in nonsurvivors, however, falls significantly in the later stages of burn injury, suggesting perhaps a defect in stem cell production and/or differentiation in patients with severe thermal injuries. The mechanism is unclear but its delineation may have an important bearing on understanding the nature of infectious complications following thermal injury.