A crystalline salt of 2-[(1R)-3-[bis(l-methylethyl)amino]-1-ρhenylρropyl]-4-methyl-phenol with (2R,3R)-2,3-dihydroxybutanedioic acid, known under the name R-tolterodine tartarate, wherein: a) at least 90 % of all crystals are present in a size smaller than 30 μm, b) at least 40 % of crystalline matter are smaller than 250 μm, c) the maximum size of crystals does not exceed 800 μm, d) the salt contains less than 0.1 weight % of the undesirable enantiomer S-tolterodine tartarate, e) analytical test for sulfate ashes (Pharm. Eur.) provides a value lower than 0.1%. The method of its preparation involves at least one crystallization from water. A pharmaceutical composition containing tolterodine or its pharmaceutically acceptable salts further contains a filler, a disintegrant and a lubricant, said composition being free of ions of alkaline earth metals.