Objectives To determine the role of miR-190b in radio-sensitivity of gastric cancer (GC). Results In radio-resistant GC cells, down-regulation of miR-190b and up-regulation of Bcl-2 were observed. The protein expression of Bcl-2 was negatively regulated by miR-190b. Overexpression of miR-190b significantly decreased cell viability and enhanced radio-sensitivity of GC cells. Of note, these effects of miR-190b on GC cells radio-sensitivity were abolished by Bcl-2. Conclusion miR-190b confers radio-sensitivity of GC cells, possibly via negative regulation of Bcl-2.