BACKGROUND Currently, primary care for the older, vulnerable patient is reactive, fragmented and does not meet patients needs. Given the expected increase of home-dwelling frail elderly people a transition is needed to proactive and integrated care. METHODS In the described study, we explore two innovative interventions in primary care. First we describe a newly developed screening and monitoring program for frail elderly patients based on routine care information in general practice. Second, we describe a multidisciplinary intervention program by trained nurses for frail elderly patients in general practice. The effectiveness of the interventions is examined in a three-armed, cluster randomized trial, taking place in 58 primary care practices in Utrecht, the Bilt and Maarsenbroek. RESULTS Three thousand eight patients are included. Primary outcome measure is the impact of the interventions on the daily activities, measured with the Katz questionnaire. Secondary outcomes measures are the quality of life, mortality, recording in a care or nursing home, visit to an emergency room or outpatient unit, recording in the hospital and volunteer caregivers tax.