Objectives Prostate cancer may affect quality of life in men diagnosed as well as their spouses. Changes in health may disrupt the couple's relationship functioning which disrupts recovery. This study examined how mental and physical health relates to relationship satisfaction for couples at diagnosis through the year following treatment. Methods Patients with stage I–II prostate cancer and their spouses (N = 159 couples) were recruited from a urology clinic and completed questionnaires at diagnosis, 1 month, 6 months, and 12 months post prostatectomy on demographics, mental and physical health quality of life, and relationship satisfaction. The Actor–Partner Interdependence Model was employed to examine effects of each partners' mental and physical health on their own and their partner's relationship satisfaction. Results Patients and spouses had declined mental and physical health at 1 month post‐surgery. Health improved at 6 and 12 months but did not fully return to pre‐surgery levels. Actor effects showed that patient's physical health consistently predicted own relationship satisfaction. Both patient's and spouse's mental health consistently related to their own relationship satisfaction. Partner effects showed that patient's and spouse's physical health had an effect on each other's relationship satisfaction at 1 month. Spouse's mental health predicted patient's relationship satisfaction throughout the year following treatment. Conclusion The effects of patient and spouse mental and physical health quality of life on their own as well as their partner's relationship satisfaction differed across time which will inform psychosocial interventions for couples with prostate cancer. Copyright © 2015 John Wiley & Sons, Ltd.