Background. Although acute complications necessitating emergency hospital admission are well documented in patients with carcinoma of the colon, comparable data for patients with gastric carcinoma is thin. The aim of this study, therefore, was to examine the outcomes of patients presenting to hospital as acute admissions with emergency complications of previously undiagnosed gastric cancer. Methods. Three hundred consecutive patients with gastric adenocarcinoma were studied prospectively, and subdivided into two groups according to whether the patients were referred as acute emergencies (n ؍ 116) or as outpatients (n ؍ 184). Resuslts. The commonest emergency complications were: abdominal pain (57%), vomiting (41%), gastrointestinal bleeding (37%), dysphagia (26%), and a palpable mass (18%). Stages of disease were significantly more advanced in patients presenting acutely (I : II : III : IV ؍ 7 : 11 : 27 : 71) compared with patients referred via outpatients (20 : 23 : 50 : 91, 2 ؍ 3.955; DF, 1; P ؍ 0.047). R0 gastrectomy was significantly less likely after acute presentation (23 patients; 20%) compared with patients referred via outpatients (70 patients; 38%; 2 ؍ 11.037; DF, 1; P ؍ 0.001). Cumulative 5-year survival for patients referred acutely was 9%, compared with 22% after outpatient referral ( 2 ؍ 9.11; DF, 1; P ؍ 0.0025). Multivariate analysis revealed two factors to be significantly and independently associated with durations of survival: stage of disease (hazard ratio [HR], 1.742; 95% confidence interval [CI], 1.493-2.034; P ؍ 0.0001) and presentation with acute complications (HR, 1.561; 95% CI, 1.151-2.117; P ؍ 0.004). Conclusion. Emergency complications of gastric cancer are a significant and independent prognostic marker of poor outcome.