Introduction Acinetobacter calcoaceticus is a non fermentative aerobic Gram-negative bacillus which is widely dispersed in nature. Several outbreaks of nosocomial infection due to A. calcoaceticus have been reported, often in association with contamination of hospital equipment or the hands of personnel (Glew, Moellering & Kunz, 1977; Buxton, Anderson, Werdegar & Atlas, 1978). In a recent report from the Communicable Disease Centre, U.S.A. (1979) in a 4 years’ survey of nosocomial infections caused by acinetobacter 1 per cent of the isolates (12 strains) were isolated from central nervous system infections. Because of the difficulty encountered in treating such infection, we report two patients with acinetobacter meningitis who were successfully treated at the Leeds General Infirmary.