Background: Letrozole is an oral non-steroidal inhibitor of the aromatase enzyme, which has proven to be a useful drug against breast cancer. Methods: This single-dose, randomized $2{ imes}2$ crossover study was conducted in healthy male volunteers. Participants of each sequence group (each 13 volunteers for sequence group) received, in randomized sequence, a single oral 2.5-mg dose of generic letrozole (test) or branded letrozole (reference). Each treatment period was separated by a 5-week washout period. Blood samples were collected for up to 312 hours after drug administration, and drug concentrations were determined using validated LC/MS-MS. Pharmacokinetic properties were obtained using noncompartmental analysis. Drug tolerability was assessed throughout the study, using measurements of vital signs, physical examination, clinical chemistry testing, EKG, and interviews. Results: A total of 26 subjects completed the study. The geometric mean ratios (90% CI) of $C_{max}$ and $AUC_{last}$ were 0.92 (0.85 - 0.99) and 1.01 (0.97 - 1.04), respectively. No serious AEs were reported, and there were no clinically significant differences between test and reference groups. Conclusion: The findings from this study suggest bioequivalence between two formulations of letrozole in healthy male volunteers. The safety profile of two formulations had similar characteristics.