In the asymptotic limit, the interlayer exchange coupling decays as D⁻² , where D is the spacer thickness. A systematic procedure for calculating the preasymptotic corrections, i.e., the terms of order D⁻n with ge3, is presented. The temperature dependence of the preasymptotic corrections is calculated. The results are used to discuss the preasymptotic corrections for the Co/Cu/Co(001) system.