Turbulent heat transfer in a two-dimensional serpentine channel with a series of right-angle turns was numerically studied. The standard k-epsilon model was incorporated for turbulence closure. The governing equations were solved by the finite volume technique, The numerical model was validated by comparing the predicted Nusselt number distributions with the experimental data obtained by the naphthalene sublimation technique. The comparison of numerically predicted values of average Nusselt number with the experimental data was fair with a maximum error of 17.4%. Calculations were made for a wide range of geometric and flow parameters (Re = 15 000-60 000). Consideration was given to high (Pr = 7.0) and low (Pr = 0.7) Prandtl number fluids. Correlations for average Nusselt number and frictional factors were developed using the method of least squares. Heal transfer was found to be more sensitive to the Reynolds number in a high Prandtl number fluid than for a low Prandtl number fluid. The maximum values of heat transfer enhancement and friction factor were found in channels with a relatively small undulation height (1-1.5 times the channel width).