85 uninstructed children aged 11-13 years brushed their teeth and were unaware that they were recorded on video tape. By viewing the films, the time spent brushing in each of 16 areas of the dentition and the number of strokes used in each area were obtained. The mean overall brushing time was 60.3 s (+/- 23.8); the mean number of strokes used by each subject was 397 (+/- 224). More time was spent and more strokes employed brushing mandibular than maxillary arches, labial and buccal than occlusal areas, and occlusal than lingual areas. The percentages of time spent and number of strokes used brushing lingual areas were low.