Fear of progression (FoP) is one of the most prevalent symptoms in cancer patients. This chronic disease does not only have a profound impact on patients, but also on their spouses. The aim of this study was to evaluate the psychometric properties of a spouse FoP questionnaire (FoP-Q-SF/P) in 227 partners of chronically ill patients (breast cancer, prostate cancer, and diabetes mellitus) in Germany. Estimates of reliability were high (α = 0.88). The original one-factor structure of the FoP-Q-SF for patients was replicated. We used the Hamilton Anxiety and Depression Scale, Impact of Event Scale-revised, Short Form-8 Health Survey, Quality of Marriage Index, Partnership Questionnaire, and Dyadic Coping Inventory to validate the FoP-Q-SF/P. Significant positive correlations were found for anxiety, hyperarousal and intrusion (r > .61) as well as for depression and avoidance (r > .51). Partners of patients with cancer reported significantly higher levels of FoP than did partners of patients with diabetes mellitus. The FoP-Q-SF/P is a reliable and valid instrument that can be recommended for further use in research and clinical care.