A group of 89 children residing in an orphanage, situated about 12 km from Vellore town, Tamil Nadu, India, were surveyed for streptococcal pyoderma, every month, from October 1976 through to December 1978. The prevalence rate of pyoderma as defined by the isolation of group A streptococci (GAS) was 10.1% with monthly variations from 2.1% to 17.1%. Three meteorological data, namely, temperature, humidity and rainfall did not show any significant relationship with seasonal patterns of pyoderma. However, a hot and humid climate, prevalent for most of the year in Vellore, may be linked to the endemicity of this condition. Studies performed on a limited number of GAS strains showed a variety of M types in the lesions. During this survey, poststreptococcal glomerulonephritis (PSGN) was not detected. In one child, a moderate albuminuria was observed; this resolved subsequently. We attest that an active surveillance of detection and treatment of pyoderma in a highly susceptible population plays an important role in the prevention of PSGN.