During the past four years, the Pediatric Department of the Columbia Medical Plan, a Johns Hopkins affiliated Health Maintenance Organization, has developed a home culture program in which parents are taught to obtain throat cultures from their children at home when symptoms appear, with a subsequent visit only if the culture is streptococcal-positive. This study was done to assess parents' accuracy by (1) a direct comparison of culture results between parents and health assistants at the clinic (group 1) and (2) an evaluation of children with negative cultures taken by parents at home, measured by the need for subsequent clinic visits (group 2). The attitudes of 70 participating families toward the program were also elicited. Families were selected on subjective criteria by the pediatric staff which instructed parents in technique and indications. Culturettes were taken home to be used as needed. Of 137 children in group 1, 24.8% were streptococcal-positive. Comparisons between health assistant and mother revealed agreement in 136 out of 137 specimens. In group 2, 28% of 100 children were streptococcal-positive; of those who were initially streptococcal-negative, 4.2% appeared within three weeks for an illness with a positive culture, compared to 4.7% in group 1. Two thirds of families felt our home culture approach improved medical care, and stated it reduced anxiety, decreased contagion, and eliminated unnecessary visits for children and their siblings. The data strongly suggest that a trained mother can play a major role in promptly and accurately identifying streptococcal throat infections without consulting a health care provider.