The objective was to explore the impact of the quality of nurse-physician communication on the quality of psychotropic drug use in Swedish nursing homes, while controlling for resident mix and other nursing home characteristics. Data were collected from a sample of 36 Swedish nursing homes providing care for 1645 residents. Drug use data, along with residents' demographic characteristics, were obtained from residents' medication administration lists. Ward nurses reported other residents' characteristics (e.g. diagnosis and frequency of behavioral problems), and facility characteristics were obtained from head nurses. The quality of drug use was assessed and cross-sectional relationships among study variables were compared. Outcome measures included two drug use quality scores reflecting selection of drug and polymedicine. To assess behavioral problems, a list of the most commonly observed problems was created through a number of steps, including focus groups in the target population. Furthermore, a valid and reliable scale for assessing communication quality was developed. This measure was included in a survey administrated to nurses in the 36 facilities. There was a remarkable variation in the quality of drug use according to the two drug measures. As predicted, the quality of drug use was positively associated with the quality of nurse-physician communication and with regular multidisciplinary team discussions addressing drug therapy and negatively associated with prevalence of behavioral disturbances among residents. Facility size, level of staffing, resident's diagnostic mix, and demographic mix were unrelated to the two drug quality measures. Future efforts to improve the quality of drug use in long term facilities should consider ways of improving communication skills and communication routines among health care professionals.