Gastric cancer (GC) is among the most frequent malignant diseases. Despite advances in treatment, the clinical outcome of patients with GC remains poor. The establishment of novel biomarkers is urgently required for early detection, treatment evaluation and prognostic assessment. Non-coding RNAs (ncRNAs) are a key topic of intensive research due to their potential applications in the field of oncology. The long ncRNA H19 has been frequently reported as overexpressed in many cancers including GC. In the present study, the diagnostic and prognostic value of circulating H19 in GC was assessed. Higher levels of circulating H19 were identified in GC patients (n=40) compared with a control group consisting of endoscopy-verified GC-free individuals (n=42; median levels relative to GAPDH, 58.4 vs. 29.9; P=0.027). Patients with smaller tumor sizes (< 5 cm) exhibited higher H19 in their circulation compared with those with larger tumors (>= 5 cm; P=0.04). Plasma levels of H19 declined significantly upon surgical removal of gastric tumors as documented in a subset of patients [n=20; relative median levels, 146.0 vs. 15.0 (pre-surgery); P=0.003]. However, it was identified that H19 had no prognostic role in GC by the Kaplan-Meier method. In conclusion, the present findings identify H19 as potential diagnostic marker in GC.