Atrophic gastritis is a well-known risk condition for gastric carcinoma (GCA). Less is known about the risk of GCA in subjects with nonatrophic ('superficial') gastritis. To investigate this, we estimated the risk of GCA in patients with nonatrophic gastritis as compared with that in subjects with normal, nongastritic mucosa. Two hundred and forty-three consecutive GCA patients and 1408 non-GCA outpatients (controls), for whom histologic data (endoscopic biopsy) of gastric mucosa was available, were included in the study. To estimate the relative risk (RR) of GCA, the odds ratio of gastritis was calculated in patients and controls by adjusting for age and sex. The RR (95% confidence interval) of GCA in patients with nonatrophic antral gastritis and with nonatrophic pangastritis was 1.8 (1.2-2.7) and 2.5 (1.4-4.3), respectively. Correspondingly, the risks of GCA were 9.1 (5.4-15.5) in patients with atrophic antral gastritis or pangastritis (atrophy of any degree) and 4.4 (1.9-10) in those with severe atrophic corpus gastritis (severe corpus limited atrophy of 'A type'). In nonatrophic gastritis the risk of diffuse-type GCA was emphasized, whereas the risk of intestinal-type GCA was emphasized in patients with atrophic gastritis. These results indicate that an increased risk of GCA is not confined to subjects with atrophic gastritis but is also slightly but significantly increased in patients with chronic nonatrophic gastritis.