Arginine/serine‑rich coiled coil 1 (RSRC1) is a gene which plays a significant role in the constitutive and alternative splicing of mRNA and transcriptional regulation. It has been implicated in various neurological disorders, as well as in cancer. However, its role in gastric cancer (GC) remains unknown. Thus, the present study aimed to investigate the role of RSRC1 in GC. RSRC1 expression in GC tissues was determined by RT‑qPCR and immunohistochemical staining. The effects of RSRC1 on cell proliferation and migration were detected using a Cell Counting Kit‑8 assay, 5‑ethynyl‑2'‑deoxyuridine (EdU) incorporation assay and a Transwell migration assay. Western blot analysis and RT‑qPCR were used to explore the molecular mechanisms of of action of RSRC1 in GC. The results indicated that RSRC1 expression was downregulated in GC tissues compared to paired normal tissues and the reduced expression of RSRC1 was shown to contribute to a poor prognosis of patients with GC. RSRC1 knockdown promoted the proliferation and migration of GC cells. In addition, the knockdown of RSRC1 decreased the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a potent tumor suppressor gene controlling cellular growth and viability. On the whole, the findings of the present study indicate that RSRC1 functions as a tumor suppressor gene in GC and that it may exert its effects by regulating PTEN expression.