From June 1975, to May 1976, in a large family practice in St. John's, Newfoundland, a randomized controlled trial was conducted to assess the effectiveness of a family practice nurse. Effectiveness was assessed using standardized health outcome measures of physical, emotional, and social function which could be applied easily and objectively by non-clinicians to the two groups of patients under study: patients receiving conventional care and patients receiving care from the family practice nurse. After establishing the comparability of these two groups of patients at the beginning of the study, these measurements showed similar levels of physical, emotional, and social function in the two groups after 1 year of receiving either family practice nurse or conventional care. These results agree with previous controlled trials of family practice nurses which have indicated that family practice nurses are effective and safe.