Abstract: The present invention relates to a process for the preparation of ticagrelor, which provides a product of high purity, in particular, with no detectable levels of Nnitrosmine impurities. The process comprises a first step of treating 2- [[(3aR,4S,6R,6aS)-6-[[5-amino-6-chloro-2-(propylthio)-4-pyrimidinyl]amino]tetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-yl]oxy]ethanol starting material with sodium nitrite, followed by acidic washing; in a second step, the 2-[[(3aR,4S,6R,6aS)-6-[7-chloro-5-(propylthio)-3H-1,2, 3-triazolo[4,5-d]pyrimidin-3-yl]tetrahydro-2,2-dimethyl-4H- cyclopenta-1,3-dioxol-4-yl]oxy]ethanol obtained in the previous step is coupled with trans-(1 fl,2S)-2-(3,4-difluorophenyl)cyclopropylamine, and the reaction is followed by a first washing at basic pH a second washing at acidic pH; and in an third step, the compound obtained in the previous step is deprotected by treatment with mineral acid, followed by acidic washing.