BACKGROUND: Relatives of older people are often involved in their care prior to hospital admission, and may hold valuable knowledge which, if involved, could improve decision-making related to care. Hence, collaboration is required and to monitor this, valid and feasible instruments are needed. The Family Collaboration Scale (FCS) was developed for this purpose, and has been found valid and reliable. Our study tested a shorter version, while assessing collaboration between nurses and 388 relatives. RESULTS: The study provided support for reliability and construct validity of the revised scale. Its feasibility may benefit from adjustments, as older relatives, those with less education and those delivering extensive help, were less likely to complete the scale. Collaboration was rated as poor to average. Poor collaboration was significantly more often reported by women and relatives reporting guilt and powerlessness.