Abstract: OBJECTIVE To investigate the relativity of dissolution profile in vitro and bioavailability of irbesartan of the irbesartan-hydrochlorothiazide tablets. METHODS The irbesartan dissolution profiles of generic product and reference product in different mediums were determined. f2 factor was used to evaluate the profiles. A single oral dose of generic product and reference product were given to 44 healthy volunteers in a randomized crossover study. Concentration of irbesartan in plasma was determined, and the results were evaluated accordingly. RESULTS The irbesartan dissolution profiles of generic product and reference product were similar in pH 1.0, pH 4.5 mediums, but were dissimilar in pH 4.5+0.4%SDS, pH 6.8, pH 6.8+0.5%Tween 20 mediums. The bioavailability was equivalent. CONCLUSION The in vitro dissolution behavior could only be reference for in vivo performance for this product.