An outbreak of blackhead disease (Histomonas meleagridis) in farm-reared flock of 13,500 bobwhite quail (Colinus virginianus) resulted in mortality totaling approximately 1500 in 4 wk. Necropsy of 56 dead birds at midoutbreak (from a total that day of 131) revealed that 55 had severe cecal lesions typical of blackhead, and only 3 had visible lesions in the liver. Necropsy of apparently healthy birds failed to detect any signs of infection. Presence of H. meleagridis in affected ceca was proved by culture in vitro and PCR tests.