The Caregiver Reaction Assessment Scale (CRA) is an instrument designed to assess specific aspects of the caregiving situation, including both negative and positive dimensions of caregiving reactions. This paper addresses the psychometric qualities of the CRA in a multicenter study among partners of colorectal cancer patients (n = 181). No problems in feasibility were observed. Five dimensions of caregiver reactions were identified through exploratory factor analysis: the impact of caregiving on disrupted schedule, financial problems, lack of family support, health problems and the impact of caregiving on caregiver's self-esteem. Reliability analyses showed that standardized Cronbach's alpha's varied between 0.62 and 0.83 for the separate subscales, indicating sufficient internal consistencies. Construct validity was supported. The CRA proves to be a feasible, reliable and valid instrument for assessing both negative and positive reactions to caregiving among partners of patients with cancer.