In some countries the valuable elements such as uranium (U), vanadium (V), Fluor (F) and the rare earth elements are recovered from phosphate rocks as by-products. There is 0,32 % Y203 in Avnik Apatite in addition to 21,5 % P2O5. A sample taken from Avnik region was ground under 100 mesh size. The sample was leached with Solutions of sulfuric acid, and the effects of acid concentration, agitation time, and solid / liquid ratio on the efficiency of leaching were investigated. When 1 hour agitation time, 10 % solid/liquid ratio, and 0,3M of sulfuric acid as leach solution are applied then the best results of the leac¬hing of yttrium were obtained.