This study aimed to investigate the bioequivalence of test and reference formulations of 40mg olmesartan medoxomil (CAS 144689-63-4) in 36 healthy male volunteers. Olmesartan medoxomil is an angiotensin II receptor antagonist used to treat high blood pressure. Volunteers were treated with two formulations of 40mg olmesartan medoxomil according to a fasting, randomised, open-label, crossover, single dose, two-period bioequivalence study design with a 14 days wash-out period. Blood samples were taken up to 72 h post-dose, the plasma concentrations of olmesartan medoxomil were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). AUC(0-infinity), AUC0-last, C-max and T-max were calculated for both formulations. The parametric 90 % confidence intervals for the primary target parameters were between 90.73-102.34 for AUC(0-last), 91.13-102.47 for AUC(0-infinity) and between 90.17-102.85 for C-max. The acceptance ranges prospectively defined in the protocol for this trial were fulfilled. Based on the available information it was determined between the bioequivalence acceptance range (80-125%). This single dose study found that the test and the reference products met the regulatory criteria for bioequivalence in these fasting healthy male volunteers.