Six Puerto Ricans, including two women, and a Chinese-American man were accidentally exposed to acute wholebody gamma radiation from 4 to 100 roentgens (r). Their case histories show no serious morbidity. Various white blood cell variations were present. At an exposure of 18 r and more, a neutrophilia and lymphopenia occurred about the fourth day. A daily plot of the neutrophils and lymphocytes would be of diagnostic value in future instances.