Direct compression of phenylbutazone is possible only with addition of excipients of several kinds, because its material properties are unfavourable. It is necessary to use besides disintegrant glidant, lubricant and antistatic agents too. The authors investigated the influence of two microcrystalline cellulose binders (Avicel and Heweten) for the pressability of phenylbutazone and on properties of the tablets, respectively. It was determined the physical parameters of the tablets and the dissolution characteristics of the active ingredient. It has been found, that Heweten optimized the exactness of dosage of the tablets as well as resulted in a faster dissolution than Avicel. Therefore, Heweten proved to be the more suitable binder.