Objective: To test the microRNA-181c (miR-181c) expression in tissues and plasma of gastric cancer (GC)cases, analyze any correlations, and explore the possibility of miR-181c as a potential molecular marker forGC diagnosis. Materials and Methods: Relative miR-181c expression levels in cancers and plasma from 30 GCpatients was tested using reverse transcription−real-time fluorescent quantitation PCR and compared to thatin samples from 30 gastric ulcer and 30 chronic gastritis patients. Results: The miR-181c expression level in theGC tissues was significantly higher than that in the gastric ulcer and chronic gastritis tissues (P = 0.000), as wasthe miR-181c expression level in the GC plasma (P = 0.000). We determined that miR-181c expression in GCplasma was positively correlated to its expression in the GC tissues (P = 0.000). Conclusions: The expression ofmiR-181c is upregulated in GC tissues and plasma, and the miR-181c expression level in GC plasma is positivelycorrelated to that in the corresponding cancer tissues. Plasma miR-181c is possibly a new serological markerfor GC diagnosis.