60 uninstructed adults aged 18-22 yr (agricultural students) brushed their teeth and were recorded on video tape. From repeated viewing of the tapes, the total brushing time and the numbers of strokes used in each of 16 areas of the mouth were obtained for each subject. The mean (+/- SD) brushing time was 33.0 s (+/- 12.0); the mean number of strokes employed by each subject was 302 (+/- 122). More strokes were used to brush the mandibular than the maxillary arch, labial and buccal than occlusal areas, and occlusal than lingual areas. The results are compared with those from a similar study in uninstructed schoolchildren, reported previously.