In addition to operating and design parameters, the thermal performance of heat exchangers, working in cryogenic temperature range, is strongly governed by losses such as longitudinal conduction through the wall, heat-in-leak from the surroundings, flow maldistribution, etc. In this paper, a three-fluid cryogenic heat exchanger, involving thermal interaction between all the three-fluids, is investigated for the effect of longitudinal heat conduction in the separating walls on its performance. (C) 2013 Elsevier Ltd. All rights reserved.