We performed a theoretical investigation of the interaction of point defects (vacancy and self-interstitials) with an intrinsic stacking fault in silicon using ab initio total-energy calculations. Defects at the fault and in the crystalline environment display a different behavior, which is evidenced by changes in formation energy and electronic structure. The formation energies for the vacancy and the [110]-split interstitial are lower at the intrinsic stacking fault than those in the crystal, indicating that in nonequilibrium conditions, intrinsic stacking faults can act, together with other extended defects, as a sink for point defects, and also that in equilibrium conditions, there can be a higher concentration of such defects at the fault than that in bulk silicon. [S0163-1829(99)03631-0].60747114714