Background Currently, there are no circulating diagnostic biomarkers for gastric neuroendocrine neoplasms (g-NENs). In previous studies, we found that miRNA-202-3p is overexpressed in the tumour tissue of type 1 g-NEN. We speculated that miRNA-202-3p is also likely to be highly expressed in circulating blood. Methods A total of 27 patients with type 1 g-NEN and 27 age- and sex-matched control participants were enrolled in this study. The miRNA-202-3p levels in serum obtained from the participants were measured by qRT-PCR. The expression level of miRNA-202-3p in the samples was calculated by comparison with a standard curve. Results The clinical characteristics of the patients were similar to those of the patient samples in previous reports. Expression of miRNA-202-3p was significantly higher in the patient group (3.84 x 10(7) copies/nl) than in the control group (0.635 x 10(7) copies/nl). The area under the ROC curve (AUC) was 0.878 (95% CI: 0.788-0.968), and the optimal cut-off point was approximately 1.12 x 10(7) copies/nl. The sensitivity and specificity were 88.9% and 77.8%, respectively. Conclusion This study suggests that miRNA-202-3p is potentially useful as a biomarker of type 1 g-NEN; further investigation and verification should be performed in future research.