We report a 32-year-old patient who underwent laparoscopy with classical symptoms and signs of acute appendicitis. An inflamed, edematous and non-perforated appendix, also a large amount gelatinous ascites, omental and peritoneal implants were seen. Appendectomy was performed and multiple biopsies were taken from omentum and peritoneum for definitive diagnosis. Histopathologic diagnosis was a metastatic gastric signet-ring cell carcinoma (GSRCC) involving appendix and other specimens. A flat lesion involving corpus to antrum was diagnosed by gastroscopy and GSRCC was verified histopathologically in a tertiary centre and the case evaluated as stage IV gastric carcinoma. This case with no sign of gastric cancer was presented as an acute appendicitis. Metastatic carcinoma to the appendix, causing acute appendicitis is extremely rare in clinical practice and usually associated with high morbidity and mortality.