We discuss the Bose-Einstein condensation (BEC) for an ideal gas of bosons in the framework of Tsallis’s nonextensive statistical mechanics. We study the corrections to the standard BEC formulas due to a weak nonextensivity of the system. In particular, we consider three cases in the D-dimensional space: the homogeneous gas, the gas in a harmonic trap and the relativistic homogenous gas. The results show that small deviations from the extensive Bose statistics produce remarkably large changes in the BEC transition temperature. PACS numbers: 05.30-d; 03.75.Fi 1 A decade ago, Tsallis introduced a nonextensive statistical mechanics (NSM) to describe systems for which the additivity property of entropy does not hold. 1 The NSM can describe systems for which long-range microscopic memory, fractal space-time constraints or long-range interactions affect the thermalization process. 2 The NSM is characterized by a parameter q such