The aim of this study was to evaluate the prognostic significance of the Goseki factor in patients undergoing potentially curative resection for gastric cancer. From 1989 to 1999 202 patients with gastric cancer came in for observation to the Ist Surgical Clinic of Catania University. For the purposes of this study we examined 86 patients with a 5-year follow-up, from whom it was possible to obtain samples which were mounted in paraffin blocks and stained (haematoxylin-eosin and PAS-Alcian blue). The 5-year survival rates of patients with Goseki I and II tumours with good tubular differentiation were 90% and 30% as compared with 42% and 32% in patients with tumours that showed poor tubular differentiation (Goseki III and IV). In contrast, the 5-year survival rates in patients with mucin-poor tumours (Goseki I and III) were 90% and 42%, as against 30% and 32% in patients with mucin-rich tumours (P < 0.05). Our conclusion is that of the two components of the Goseki system, i.e. tubular differentiation and intracellular mucus, mucus production was found to be the more important determinant of clinical outcome. Mucus production has a greater impact on survival than the degree of tubular differentiation and is independent of it.