Trained reviewers audited 10,500 charts in the offices of 166 pediatricians and family physicians. Criteria for child health supervision and three diseases had been previously validated for relevance to health outcome and suitability for peer review. Overall documentation of criteria was approximately 50 per cent. Measurements and laboratory data were recorded frequently; counseling items infrequently. Pediatricians documented health supervision items more often than family physicians. Members of large groups recorded more than those in solo practice or small groups. The presence of equipment considered important for health care did not correlate with percentage of recording. The method of review was judged accurate and acceptable by physicians, but only 50 per cent said the results accurately portrayed their performance. Lack of accurate recording may make it impossible to achieve valid peer review of ambulatory child care.