Background: Immunohistochemical prognostic significance of the homologous recombination-related proteins RAD51, ATM, BRCA1, and BRCA2 is known in gastric adenocarcinoma, one of the deadliest cancers. Objective and design: This retrospective cohort study aimed to evaluate mRNA expression and promoter methylation of some homologous recombination-related genes in this neoplasm. Methods: We evaluated mRNA expression and methylation of RAD51 , ATM , ATR , BRCA1 , and BRCA2 in tumor and non-tumor frozen samples from gastrectomy specimens by RT-qPCR and MS-HRM, correlating our results with previous immunohistochemistry data and prognostic features. Results: RAD51 , ATR , BRCA1 , BRCA2 , and ATM mRNA expression was detected in 93.75% (45/48), 93.75% (45/48), 91.67% (44/48), 83.33% (40/48), and 89.58% (43/48) of the tumors; partial or complete methylation, in 94.87% (37/39), 0 (0/42), 97.56% (40/41), 100% (41/41), and 0 (0/40), respectively. Most gene pairs showed significant weak to moderate positive correlations of tumoral mRNA expression with each other: RAD51 with ATR ( P = .027), BRCA1 ( P