In an abattoir survey the stomachs of 1242 pigs from 15 farms were examined. Ulceration of the pars oesophagea was present in 22.95 per cent with a range from 4.7 to 57.4 per cent. The ulcers were graded mild in 9.5 per cent and severe in 13.4 per cent of the stomachs. Bile staining and hyperkeratinisation of the pars were significantly more common in stomachs with ulcers than in those without (P<0.001), although the difference between the hyperkeratinisation in cases with severe ulcers and cases without ulcers was not significant. The daily liveweight gains of 208 males and 150 females from two units with a high prevalence of ulcers were calculated from their weaning weights at about five weeks of age and their slaughter weights at around 90 kg. At the abattoir their stomachs were examined for the presence of ulcers of the pars. The daily liveweight gain of the males was significantly greater than that of the females (P<0.001), but the presence of mild or severe ulcers had no influence on the rate of gain of the pigs from either unit. The prevalence of ulcers in the males and females was 57.2 and 49.3 per cent, respectively, but the difference was not significant.