This experimental study aims to investigate the heat transfer characteristics of single-phase turbulent flow of R 134a refrigerant in a rectangular multi-micro channel heat sink having 27 channels where each channel has a hydraulic diameter of 421 pm. Experimental results were obtained for inlet temperatures ranging from 24 to 33 degrees C, mass fluxes from 1485 to 2784 kg m(-2) s(-1) and wall heat fluxes from 3 to 24 kW m(-2). The results indicate that the heat transfer coefficients are found to be higher at lower inlet temperatures than those at higher ones. In addition, when equal amount of heat supplied to the heat sink, the heat transfer coefficients increase with increasing the mass flux of refrigerant. They were also compared with 12 well-known correlations and it was seen that 4 of 12 were in good agreement with each other with the average deviation < 10%. The findings demonstrate that well-known correlations in fundamental sources can be used to predict the heat transfer coefficient of R-134a during its single phase flow in a multipart microchannel heat sink under turbulent regime.