Abstract 1. 1. Of 413 rheumatic children observed over a period of from one to ten years, 247 were subjected to tonsillectomy. 2. 2. Manifestations of infection recurred in 47.7 per cent and appeared for the first time in 34.7 per cent of the treated children. 3. 3. In only 17.5 per cent was there no manifestation of rheumatism after the operation. 4. 4. In rheumatic children less than nine or ten years of age, recurrent attacks were frequent, whether or not tonsillectomy had been performed. In older children recurrent attacks became less frequent regardless of enucleation of tonsils. 5. 5. The age at which tonsillectomy was performed and not the fact of tonsillectomy appeared to be the significant factor in the incidence of nonrecurrence of infection after operation.