Warfarin is a drug with narrow therapeutic index. Individualization of dose and thorough therapy monitoring is compensated by long time use in praxis and low therapy cost. Considering the low dose usually administered, critical parameter of solid dosage form is its uniformity of content. It has to not only meet the criteria set by pharmacopoeia, but to meet them on statisticall significant level also.This experimental study asseses impact of warfarin concentration and blending time after adition of lubricant on uniformity of content of mixtures and tablets made of them. It concludes, that concentration in 2-2,7% range is optimal and its increase or decrease has a negative effect on uniformity of content. It also confirms 5 minutes of blending after lubricant addition to be adequate, as employing longer blending times leads to mixture overblending.Key words: content uniformity warfarin blending time narrow therapeutic index.