In this paper, the probability of power depletion due to stimulated Raman scattering (SRS) is derived for an arbitrary number of interferers to estimate bit error rate and power penalty of a wavelength division multiplexed (WDM) receiver. Gaussian function approximation can be used only when the numbers of interferers is very large. The effects of number of interfering channels, channel separation and receiver noise on the bit error rate (BER) are studied. Minimum BER varies non-monotonically with channel separation. Optimum detection thresholds for minimum BER in the WDM receiver in presence of SRS crosstalk are investigated and summarized in tabular form. © 2006 IEEE.