In recent years, the emphasis on regular cancer screening programs and advances in diagnostic techniques has greatly improved the detection rate of early gastric cancer (EGC). Gastric cancer (GC) is the fourth most common cancer and the second leading cause of cancer-related death worldwide, and is especially prevalent in the Asia-Pacific region. Further external validation with independent patient cohorts is required to improve the accuracy of prediction. Individual risk of developing metachronous MPC could be predicted by a novel nomogram. Patients at high risk of developing metachronous MPC after curative resection of GC were identified. Furthermore, we were able to develop and internally validate a nomogram to predict the metachronous MPC after curative gastrectomy (C-index = 0.72). In addition, patients with a metachronous MPC showed late survival disadvantage, while patients with a synchronous MPC showed early survival disadvantage. GC patients with either metachronous or synchronous MPC showed poorer survival than patients without MPC. Multivariate logistic regression analysis revealed that old age at the time of GC diagnosis (≥60 years), early stage of GC (stage I and II), and multiplicity of GC at the time of gastrectomy were independent predictive factors for metachronous MPC. The most prevalent site of metachronous MPC was the colorectum (26.3%), followed by lung (23.7%) and liver (18.4%). Of these, 54.3% had a metachronous MPC, while 45.7% had a synchronous MPC. Methodsģ066 patients who underwent curative resection of GC were reviewed retrospectively, based on the clinical information and the medical record. The purpose of this study is to evaluate the clinicopathological features of MPC and to generate useful tools for the prediction of metachronous MPC following gastrectomy. Due to improved survival rate, gastric cancer (GC) patients have an increased risk of developing multiple primary cancer (MPC).