The objectives of the study were to assess whether an inservice education program for nurses in long-term care facilities was effective in increasing the nurses' knowledge of drugs and whether the increased knowledge affected nurses' behavior regarding drug therapy monitoring. The four-phase study was conducted in two study homes and two control homes and consisted of pre-tests, inservice, post-tests, and a three-month evaluation period. There results indicate that nurses in the study homes demonstrated a statistically significant increase in drug knowledge, and this was reflected in an objective change in behavior to more appropriate monitoring of drug therapy. It may be concluded that intensive inservice education programs are an effective method for inducing behavioral changes in nurses working in long-term care settings. These changes can improve the nurses' ability to monitor and promote safe and efficacious drug therapy in long-term care facilities.