The influence of information factors on the follow-up of patient problems was studied in six ambulatory clinics providing primary patient care. By means of chart review, the encounter notes were examined for two consecutive visits to the same clinic to determine problems identified at the first visit and detect evidence of follow-up of these problems at the second visit. In those clinics using a problem list, at the front of the chart, those problems on the problem list had a higher follow-up rate than those not on the list particularly at longer intervals between patient visits. An encounter note written in the problem-oriented format did not enhance follow-up. Since information factors as well as clinical factors affect the follow-up of patient problems these factors must be carefully considered when designing information systems to serve ambulatory care.