A scheme offering joint health and social care assessments to people aged over 75 in inner London identified more than a quarter in need of services. The older people were accessed via general practice, but this proved an inefficient way of identifying the target population. In some practices, almost half of those contacted were no longer at the same address. The assessments, conducted by a community nurse and social welfare officer, often involved two visits. The mobility of the elderly population needs to be taken into account when planning joint assessments. Organisations involved had different aspirations for the scheme and management proved problematic.