Background Physiological and psychological changes during menopause can affect the quality of marital satisfaction. The aim of this study was to evaluate the effect of self-care education program on the severity of menopause symptoms and marital satisfaction in postmenopausal women. Methods In this randomized controlled clinical trial, 70 postmenopausal women who referred to the gynecology clinic of Baqiyatallah and 502 Artesh hospitals in Tehran, Iran, and met the all inclusion criteria were randomly allocated into two equal groups (intervention and control groups) using block randomization. The intervention group received self-care training program in physical, psychological, social and sexual dimensions in 5 sessions during a week. The control group also had 5 sessions exactly the same as the intervention group, except that they received only routine care and training. Data were collected pre- and post-intervention using Menopause Symptoms' Severity Inventory (MSSI-38) questionnaire and the Revised Dyadic Adjustment Scale (RDAS) questionnaire. Results In the control and intervention groups before the intervention, socio-demographic characteristics (P > 0.05), the mean scores of MSSI-38 (P = 0.388) and RADS (P = 0.476) were not statistically significant. However, in the intervention group the mean scores of MSSI-38 (49.88 ± 3.3 vs. 39.33 ± 3.7, P < 0.001) and RADS (35.15 ± 4.3 vs. 49.48 ± 3.2, P < 0.001) after the intervention changed significantly and this change were statistically significant compared to the control group. Significant inverse correlation between severity of menopausal symptoms and marital satisfaction was observed with r = -0.461, P < 0.001. Conclusion Our findings indicate that self-care training has a positive effect on the severity of menopause symptoms and also improves marital satisfaction in postmenopausal women. Therefore, we recommend that more attention be paid to providing self-care educational content to improve the marital satisfaction in postmenopausal women. Clinical trial registration Iranian Registry of Clinical Trials; https://www.irct.ir/trial/49225 (IRCT20200624047910N1), registered (10/11/2020).