Designer piperazines, such as 1-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)-piperazine (TFMPP), are widely available and have become popular party drugs throughout the world. Used in many countries as legal alternatives to methamphetamine and ecstasy, these designer piperazines exhibit several of the same stimulant and psychoactive properties of their illicit counterparts. Presented is a case study of seven urine analysis specimens analyzed for designer piperazines. A full scan gas chromatography-mass spectrometry screen detected the presence of BZP and TFMPP in all seven specimens. Confirmation using liquid chromatography-electrospray ionization-mass spectrometry operating in selected ion monitoring mode (SIM) yielded urinary concentrations ranging from 13.0 to 429.1 mg/L and 0.79 to 25.4 mg/L for BZP and TFMPP, respectively.