Flunitrazepam is a potent benzodiazepine that is subject to abuse and malicious use. This study describes the patterns of flunitrazepam abuse and malicious use calls received by Texas poison centers during 1998-2003. The distribution of calls by year of call, geographic location of caller, patient gender and age, exposure site, and medical outcome were determined. There was no clear annual trend for abuse calls, but there was a consistent decline in the number of malicious use calls. A significantly higher percentage of abuse calls originated in south and west Texas and of malicious use calls in west Texas. Most abuse patients were males (55%) and adolescents (76%), and most of the exposures occurred in patient's own residence (68%), followed by school (16%). Most of the malicious use patients were females (93%) and adults (74%), and the greatest proportion of the exposures occurred in public areas (47%), followed by the patient's own residence (26%). The highest percentage of both abuse (48%) and malicious use (55%) involved minor effects. However, malicious use calls were significantly less likely to involve no effect (2% vs. 21%) and more likely to involve moderate effects (36% vs. 23%). Reported flunitrazepam abuse and malicious use calls in Texas differed with respect to geographic location of the caller, patient gender and age, exposure site, and medical outcome. Poison centers and health care providers might want to consider these differences when targeting populations for education and prevention efforts.