L'integration de l'Asie centrale dans le monde musulman est ici analysee a travers le sort de ses elites nobiliaires et militaires, aussi bien iraniennes que turques, au VIIIe et au IXe siecle. Celles-ci parviennent au pouvoir en Iraq avec les califes Ma'mun et Mu'tasim. Elles transposent a Bagdad et Samarra leurs hierarchies centre-asiatiques et les elites abbassides sont pendant un demi-siecle sous leur influence. Mais la desagregation lente du systeme militaire organise autour d'elles a Samarra conduit aux troubles des annees 860. Le systeme mamelouk nait apres 870 de sa mutation afin de mieux maitriser les gardes turcs. The integration of Central Asia into the Islamic empire during the VIIIth and IXth c. is here analyzed through the history of its nobility and military elites. With the caliphs Ma'mun and Mu'tasim, these nobles and soldiers, both Iranian and Turkish, took part in the government of the Muslim Empire in Iraq. They brought to Baghdad and Samarra their Central Asian hierarchies and the Abbasid elites were under their influences for half a century. But the slow decay of this Central Asian military system in Samarra gave way to the political disorders of the 860's. The mamluk system was then created in the 870's to better manage the Turkish cavalrymen.