Peritoneal carcinomatosis (PC) is an important cause of morbidity and mortality among patients with gastric cancer. The aim of the current study was to provide reliable population-based data on the incidence, risk factors and prognosis of PC of gastric origin. All patients diagnosed with gastric cancer in the area of the Eindhoven Cancer Registry between 1995 and 2011 were included. Incidence and survival were computed and risk factors for peritoneal carcinomatosis were determined using multivariate logistic regression analysis. In total, 5,220 patients were diagnosed with gastric cancer, of whom 2,029 (39%) presented with metastatic disease. PC was present in 706 patients (14%) of whom 491 patients (9%) had PC as the only metastatic site. Younger age (<60 years), female gender, advanced T- and N-stage, primary tumor of signet ring cells or linitis plastica and primary tumors covering multiple anatomical locations of the stomach were all associated with a higher odds ratios of developing PC. Median survival of patients without metastases was 14 months, but only 4 months for patients with PC. PC is a frequent condition in patients presenting with gastric cancer, especially in younger patients with advanced tumor stages. Given the detrimental influence of PC on survival, efforts should be undertaken to further explore the promising results that were obtained in preventing or treating this condition with multimodality strategies. What's new? Until recently, peritoneal carcinomatosis (PC), in which malignant ascites forms in the peritoneum, was considered to be an untreatable condition. But new treatment options have raised hope for improved survival, as well as created a need to better understand risk factors and prevention. Here, analysis of data from the Eindhoven Cancer Registry from 1995-2011 reveals that more than one-third of patients with metastatic gastric cancer presented with PC. Younger patients and females with advanced disease were at greatest risk for this condition. The findings may have implications for PC diagnosis and treatment.