The relation between previous tonsillectomy and Hodgkin's disease was examined in a case-control study involving 81 histologically confirmed childhood cases and two sibling control groups. When cases were compared with age-matched sibling controls a significant association (p < 0.02), with a risk of 2.7, was observed for children who had undergone tonsillectomy. A significant association (p < 0.01), with a relative risk of 2.5, was also shown when all siblings were used for comparison. History of hospital admissions, age at tonsillectomy, Rye histological subtype, birth order, and sibship size did not appear to modify the effect of this operative procedure on the risk of Hodgkin's disease.