A total of 151 Enterobacter cloacae strains isolated from clinical samples (n = 139) and the hospital environment (n = 12) at a tertiary care hospital in northern India during January to October 1993, were analysed. The maximum isolations were during May (n = 24), June (n = 23) and July (n = 22). Urinary tract infection (n = 56) was the most common complication of E. cloacea infection followed by wound infection (42), respiratory tract infection (23) and bacteraemia/septicaemia (18). The frequency of resistance to different drugs was ampicillin 77.4 per cent, cotrimoxazole 79.5 per cent, gentamicin 57.5 per cent, cefotaxime 47 per cent and ofloxacin 36 per cent. Sixty three (41.7%) strains exhibited resistance to multiple drugs. Environmental isolates from bed, hospital diet, hand swab and water from a leaking drain pipe in a ward showed the same resistance pattern. A single index strain could not be identified using phage and biotyping, indicating that a variety of strains were responsible for the nosocomial infection. Adoption of strict aseptic measures and repair of the pipe brought down the infection rate.