A theoretical model for shell-side pressure drop has been developed. The model incorporates the effect of pressure drop in inlet and outlet nozzles along with the losses in the segments created by baffles. The results of the model for Reynolds numbers lying between 1 03 and 105 match more closely with the experimental results available in the literature compared to analytical models developed by other researchers for different configurations of heat exchangers. (c) 2005 Elsevier Ltd. All rights reserved.