The paper gives theoretical results for condensation on low-finned tube in which the temperature drop at the liquid-vapour interface due to interphase matter transfer (interface resistance) is included. The condensation coefficient is taken as unity. Results show, for the case of steam, that in the regions of the fin surface where the condensate film is very thin, the local heat flux can be reduced by a factor of around 2 when the interface resistance is included. Theoretical results for the top of the tube show a significant drop in average vapour-to-surface heat-transfer coefficient with decrease in vapour pressure (around half associated with interface resistance and half due to fluid property variation) in line with earlier measurements. (C) 2003 Elsevier Ltd. All rights reserved.