Measurements are presented of the distributions of heat transfer coefficients along the leading and trailing walls of a rotating two-pass rectangular channel with through flow. The channel has a 180 degrees rectangular turn and a cross-sectional aspect ratio of 1.25. The Reynolds number and rotational number were varied from 5.0 x 10(3) to 5.0 x 10(4) and 0 to 0.44, respectively. Complementary flow visualization and laser-Dopper velocimetry measurements were also performed to facilitate interpretation of the measured heat transfer distributions. The results show that the secondary flow induced by the curvature and turbulence enhancement associated with unsteadiness of separation bubble downstream of the sharp turn are responsible for the significant heat transfer augmentation attained in the first part of the second pass. Moreover, the quantitative effects of the Coriolis force on the skewness of streamwise mean velocity profiles and in turn different local and average heat transfer features in the radially outward and inward flows are demonstrated and addressed.