Fifty-nine cases of gastric dysplasia (46 of which were mild, 11 moderate and 2 severe) were studied in relation to their association with atrophic gastritis and intestinal metaplasia. Atrophic gastritis was found in 39 cases (28 of which were mild, 10 moderate and 1 severe). Dysplasia was considered "persistent" when found of the same degree in at least two consecutive check-ups after initial diagnosis (13 cases); it was considered "progressive" if found more severe or evolving as cancer (5 cases) or "regressive" if detected in a lesser degree or no longer detected (13 cases). Sixteen of the 18 persistent or progressive cases of dysplasia were associated with atrophic gastritis, whereas 10 of the 13 cases with regressive dysplasia revealed no concomitant pattern of gastric mucosa atrophy (p less than 0.005). These findings suggest that dysplasia represents a truly pre-neoplastic change particularly when associated with atrophic gastritis and which must therefore be more carefully monitored.