The abuse and misuse of benzodiazepines and zolpidem are widespread internationally. Their illegal distribution has raised their abuse to a serious level, and they are often misused in crimes. In the present study, 18 cases involving the illegal use of benzodiazepines and/or zolpidem were proved by hair analysis. The drugs were extracted from the hair samples using methanol and analyzed using LC-MS/MS. The cases were classified according to case history: five of illegal use in medical staff, eight through inappropriate or illegal distribution, and five related to drug-facilitated crimes. Among the 18 cases, zolpidem was identified in eight, alprazolam in seven, diazepam in six, and clonazepam in four. The drug concentrations ranged from <LOQ to 6.47 ng/mg. Due to the ready supply and potential for criminal misuse of these drugs, programs for prescription drug monitoring and supervision of those handling these drugs are both recommended.