PURPOSE: Distress caused by cancer may have an important impact on the quality of a couple's relationship. This investigation examined perceived relationship changes in a sample of cancer patients and their partners, accounting for gender and role (i.e., patient or partner). PATIENTS AND METHODS: A total of 209 patients with different cancer types and stages and their partners completed questionnaires with items on psychological distress (anxiety and depression), quality of life, and perceptions regarding positive and negative relationship changes. RESULTS: A total of 149 patients (71.3%) and 156 partners (74.6%) reported that the diagnosis of cancer had changed their relationship. Of these, 121 (57.9%) patients and 116 (55.5%) partners reported positive changes only, whereas eight patients (3.8%) and 18partners (8.6%) indicated negative changes only. Twenty patients (9.6%) and 22 partners (10.5%) had experienced both positive and negative changes. In male patients and partners, negative dyadic changes were associated with lower quality of life and higher levels of anxiety and depression. This finding was similar in female partners, but not in female patients. The association between perceived negative relationship changes and both increased psychological distress and reduced quality of life remained significant even when controlled for gender and congruency of perception. CONCLUSIONS: Although most couples in our sample reported growing closer while dealing with cancer, a small but sizeable percentage observed negative changes in their relationships, and these negative changes resulted in increased psychological distress and worse quality of life. Female partners were at greatest risk for these negative perceptions.