An experimental study is carried out to investigate the effect of entrance and exit conditions that prevail due to different flow arrangements on the thermal performance of a copper micro-channel heat sink. Three flow arrangements-U-type, S-type, and P-type-were considered for the analysis with a test piece having inlet and outlet plenum dimensions of 10 mm x 30 mm x 2.5 mm with an array of parallel micro-channels having an individual width of 330 mu m and a uniform channel depth of 2.5 mm. Performance evaluations for different flow conditions at inlet and outlet plenums were made by maintaining constant heat supply at 125 W, 225 W, and 375 W with varying Reynolds number ranging from 224 to 1,121. Nusselt number and pressure drop were computed by measuring temperature difference and pressure drop across the inlet and outlet plenum for various test combinations. Maximum heat transfer was observed for the U-type flow arrangement, followed by the P-type and S-type; maximum pressure drop was noted for the S-type flow arrangement, followed by the U-type and P-type arrangements for a constant Reynolds number. A detailed analysis of the experimental results indicate that from a pressure drop point of view, the P-type flow arrangement is preferred, whereas from the heat transfer point of view, the U-type is found to be a better option.