BACKGROUND: The aim of the study was to determine the value of performing peritoneal lavage cytology during laparoscopy in the management of oesophagogastric adenocarcinoma. METHODS: Laparoscopy combined with peritoneal cytology was performed in patients with potentially resectable oesophagogastric adenocarcinoma. Macroscopic peritoneal findings at laparoscopy and the presence of free peritoneal tumour cells were recorded. All patients were followed to death or the census point. Patients with overt peritoneal disease or positive cytology were offered palliative chemotherapy, subject to performance status. RESULTS: Forty-eight (18.8 per cent) of 255 patients had overt peritoneal metastases at staging laparoscopy. Fifteen (7.2 per cent) of the remaining 207 patients had positive cytology; these patients had a median (95 per cent confidence interval) survival of 13 (3.1 to 22.9) months, versus 9 (7.4 to 10.6) months for those with overt peritoneal metastases (P = 0.517). Of patients receiving chemotherapy, those without overt metastases had a slight survival advantage over patients with metastases (median 15 (10.8 to 19.2) versus 9 (7.4 to 10.7) months; P = 0.045). CONCLUSION: Positive peritoneal cytology in the absence of overt peritoneal metastases is not uncommon in oesophagogastric adenocarcinoma. It is a marker of poor prognosis even in the absence of overt peritoneal metastases.