Abstract: The metamorphic rocks of the Bitlis Massif consist of two groups which are called the lower andthe upper associations separated by an unconformity. The lower association with a possible age of Precambrian iscomposed of metavolcanics, gneisses and crosscutting granites; the upper association, which has a probable age range of Cretaceous, is composed of micaschist and marbles.The apatite - bearing iron deposits of the Bitlis Massif are in the lower ossociation and located along distinctstratigraphic horizons.In the Avnik (Bingöl) region apatite - bearing iron deposits are intercalated with metavolcanics and massive,banded and lensoidal in shape. These deposits are volcano sedimentary in origin. The ore bodies show variations alongtheir strikes and may pinch out in short distances due to irregularities in the volcanic topography where they deposited. Stratification and thin sedimentary laminae are hard-to recognize in the ore bodies. Magnetite is the dominantmineral in the deposits of this region. Contrary to the lateral irregularities of the deposits of the Avnik region, those of the Ünaldı (Bitlis) area can be followed for several kilometers along their strikes. The deposits of this second region have very regular and fine laminated distinct internal sedimentary structures. There are thinly laminated metachert intervals in the Ünaldı deposits- It is clearly demonstrated that the deposits of the Ünaldı region in which apatite is the dominant mineral, were formed by an undistirb ed sedimentation.The characteristics of the apatite - bearing iron deposits of the Avnik and Ünaldı regions, which are associatedwith metavolcanics and metaeherts, indicate that they are volcanosedimentary in origin. In the both regions the orebodies are cut and partially assimilated by younger palingenic granites. Both palingenesis and multiple metamorphism and deformation were effective in forming the complicate structures.