In this present study, attempts were made to investigate the heat transfer characteristics of a helically baffled heat exchanger combined with one three-dimensional finned tube. The experiments were carried out in counter mode operation with hot oil in the shell side and cold water in the tube side. Overall heat transfer coefficients were calculated and heat transfer coefficients in the shell and tube side were determined using modified Wilson plot. A commercial computation fluid dynamics (CFD) program called Fluent 6.0 was used to predict the flow and heat transfer performance in the heat exchanger. The numerical results agree well with the measurements. The maximum differences between the present numerical results and the experimental data are approximately 6.3% for Nusselt number and 9.8% for pressure drop, respectively. (c) 2007 Elsevier B.V. All rights reserved.