Bioequivalence testing for estimation therapeutical equivalence of generic drugs. Generic drugs have been presented on pharmaceutical market for many years. The term generic drugs is used for prescription drugs which are therapeutically interchangeable with brand-name drugs. Therapeutic bioequivalence is guaranteed by bioequivalence testing involves comparison of measures of bioavailability of the generic and reference drug. Generic substitution has become a common practice for many years. At the time, many of these generics caused bioavailability problems, which evoked suspicious about their efficacy and safety and standards for bioequivalence. No critical trials for generic products are required thus prices are lower than prices of brand-named medical products. The economic benefit of generic drugs is clear but what of the safety and efficacy of these products

Keywords: bioequivalence, bioavailability, therapeutic equivalence, generic drug.