With the aim of evaluating the prognosis of neuroendocrine tumours of the stomach we studied 255 patients with these tumours to gain informations about the different biological behaviour of these tumours. We examined subtypes on the basis of the type of gastritis according to RINDI et al. 1993. A classification was made on the basis of tumour size, depth of invasion, angio invasion, functioning or non functioning, metastatic or non metastatic according to CAPELLA et al. 1994 to estimate benign and low or high grade malignant behaviour. 191 carcinoid tumours in autoimmune gastritis were in 86.4% classified as benign tumours (88% not more than 1 cm in diameter, 1 case with lymph node metastasis, no carcinoid tumour related death). 12 carcinoids associated with ZES-MEN I showed a benign or low grade malignant behaviour (60% more than 1 cm in diameter, 2 cases with lymph node metastasis, 1 with distant metastasis, 1 carcinoid related death). 36 sporadic carcinoid tumours were in 42% low grade malignant (36% 1-2 cm size, 25% more than 2 cm in diameter, 3 cases with lymph node metastasis, 2 with distant, 6 with lymph node and distant, 7 carcinoid related death). 13 neuroendocrine carcinoma were high grade malignant (1.5-7 cm size, 6 cases with lymph node metastasis, 2 with distant, 4 with lymph node and distant, 8 carcinoma related death). Therefore we conclude that in the classifications compared carcinoid tumours in A-gastritis are-in contrast to the other types of neuroendocrine tumours of the stomach-benign tumours with a good prognosis. The type of gastritis is for the prognosis of gastric neuroendocrine tumours besides tumour size and metastasis the most important parameter.