The pressure drop and heat transfer characteristics of a single-phase micro-channel heat sink were investigated both experimentally and numerically. The heat sink was fabricated from oxygen-free copper and fitted with a polycarbonate plastic cover plate. The heat sink consisted of an array of rectangular micro-channels 231 mum wide and 713 mum deep. Deionized water was employed as the cooling liquid and two heat flux levels, q(eff)" = 100 W/cm(2) and q(eff)" = 200 W/cm(2) defined relative to the planform area of the heat sink, were tested. The Reynolds number ranged from 139 to 1672 for q(eff)" = 100 W/cm(2), and 385 to 1289 for q(eff)" = 200 W/cm(2). The three-dimensional heat transfer characteristics of the heat sink were analyzed numerically by solving the conjugate heat transfer problem involving simultaneous determination of the temperature field in both the solid and liquid regions. Also presented and discussed is a detailed description of the local and average heat transfer characteristics of the heat sink. The measured pressure drop and temperature distributions show good agreement with the corresponding numerical predictions. These findings demonstrate that the conventional Navier-Stokes and energy equations can adequately predict the fluid flow and heat transfer characteristics of micro-channel heat sinks.