This study investigates experimentally and numerically the characteristic of the pressure drop and the behavior of the fluids under the influence of the configurations of flow channel. The triangular microchannels have the transverse dimensions from 50μm to 100 μm; the fluid flowing through these channels has Reynolds numbers from 0.1 to 35. For this study, significant difference between the pressure losses obtained from the conventional macro-scale theory and those obtained from the experimental data. However, the results obtained from the conventional theory are not much different from the results obtained from the numerical simulation. For the triangular microchannel under study, the pressure loss in terms of ∫Re obtained from the experimental results is lower than those obtained from the conventional theory; the highest relative error is 27%. The revised correlation derived from the experimental results for the value of ∫Re of the fluid in the Triangular is ∫Re = 45.6; using this expression would provide a better fit to the experimental data.