The aim of this study was to evaluate the effect of the type of lubricant, its concentration and mixing time with granules on the tablet hardness, ejection force and the lubrication index. Lactose was used as a filler in granules and polyvinylpyrolidone as a binder. Granules were prepared by wet granulation. Three types of talc were used in concentrations 1%, 3%, 5%, 7% a 10% and magnesium stearate in concetrations 1%, 2% a 3% as lubricants. Tablets were produced by tablet press DOTT Bonapace (model CPR-6) with the possibility to measure the force of the upper and lower punch and force-displacement. These values were used for the calculation of the lubrication index. The values of lubrication index were used for the lubricants comparison. The lubrication index with magnesium stearate did not change either with increasing concentration or with mixing time with granules. In case of each type of talc, the lubrication effect rose with increasing concentration but time of the mixing did not have any significant effect on the lubrication potential. Tablet strength decreased with higher lubricant concentration and longer mixing time when magnesium stearate was used. With increasing concentration of the lubricant tablet strength with talc first increased then stagnated or started to decrease. The higher...