This paper deals with understanding the thermohydraulic characteristics of one type of zig-zag square microchannel. Studies are done to understand the individual effect of geometric parameters like hydraulic diameter, orientation angle and connector length for Reynolds number between 100 and 400. The hydraulic diameter is varied between 100 μm and 300 μm with increment of 100 μm. Studies are carried out for orientation angle of 10°, 20° and 30°. The connector length of the study conducted in this paper is varied from 200 μm to 400 μm to 600 μm. The results are presented in terms of enhancement of Nusselt number and Poiseuille number over that in straight square microchannels. With increase in hydraulic diameter the enhancement in Nusselt number and Poiseuille number increased at a specific Reynolds number. Similarly with increase in the orientation angle the enhancement in these two thermohydraulic characteristics is observed for a specific Reynolds number. With increase in connector length both Nusselt number and Poiseuille number increased over that in straight channels of the same hydraulic diameter for a particular Reynolds number. Enhancement in Nusselt number and Poiseuille number is observed with increase in Reynolds number for all zig-zag microchannels. For the three fold increase in each of the geometric parameters the smallest enhancement is observed with increase in connector length. The greatest enhancement in thermohydraulic characteristics is observed with change in orientation between the arm and the connector.