A cross-sectional descriptive study among Norwegian nursing homes was conducted in 2003 to examine pharmacoepidemiological characteristics of antibacterials in nursing homes and also to estimate their share of overall antibacterial use in Norway. Antibacterial data were collected for ATC group J01 antibacterials for systemic use, A07AA09 vancomycin and P01AB01 metronidazole in DDDs/y. The amount of drugs principally prescribed for urinary tract infections (UTI) were depicted and used as an indicator for the treatment frequency for UTI in the nursing homes. Prescription of antibacterials in the 133 nursing homes that delivered data varied - from 4 to 44 DDD/100 bed-d. The urinary prophylactic agent, methenamine, represented nearly half of DDDs used, mean 7.3 DDD/100 bed-d. Penicillins with extended spectrum (J01CA) were most frequently used, followed by trimethoprim and sulfonamides (J01E), mean 2.3 and 1.5 DDD/100 bed-d, respectively. On average, 49% of the therapeutic antibacterials were drugs used for UTI, range 12%-88%. In 2003, the nursing home setting purchased an estimated 6% of human antibacterial use in Norway. Nursing homes represent an important share of national human use of antibacterials. The large variation in antibacterial use between facilities underlines the need for increased focus on rational prescribing in nursing homes.