The importance of the developmental surveillance of children is generally accepted. One method which could be used in general practice is opportunistic surveillance, where the doctor makes use of contacts with children in the surgery to assess their development, and offer advice and health education to parents where appropriate. This study describes an audit of opportunistic developmental surveillance in one general practice. It was found that 95% of a cohort of 78 children had been assessed at least once by the time they were one year old. In addition, at two points in the study, after one and two years, it was found that 81% of children aged two years or less in the practice had had a recent assessment. This level of surveillance compares favourably with reported attendance rates in clinics.