Human four-and-a-half LIM domains 1 (Fhl1) gene has been reported to achieve cancer suppressive effects. The purpose of this study is to clarify clinical significance of Fhl1 expression in gastric cancer.Fhl1 mRNA expression was quantified by real-time reverse transcription (RT)-polymerase chain reaction (PCR) using paired tumor and normal clinical samples from a total of 110 gastric cancer patients. Fhl1 protein expression was investigated by immunohistochemistry. The relationship between Fhl1 mRNA expression and clinicopathological factors was statistically analyzed.Fhl1 mRNA expression in tumor tissue was significantly downregulated compared with that in normal mucosa (P < 0.0001). Fhl1 protein expression was also diminished in cancer cells by immunohistochemistry. Kaplan-Meier survival curves demonstrated that the patients with low Fhl1 expression tumor showed significantly shorter survival (P < 0.05) than those with high Fhl1 expression tumor. Furthermore, the tumors with low Fhl1 expression showed deeper invasion into the serosal layer (P < 0.05) or more frequent distant metastasis (P < 0.01).Fhl1 gene was underexpressed in clinical gastric cancer. Loss of Fhl1 expression would be a novel biomarker to determine biological aggressiveness of gastric cancer.