Natural convective flow and heat transfer in an inclined quadrantal cavity is studied experimentally and numerically. The particle tracing method is used to visualize the fluid motion in the enclosure. Numerical solutions are obtained via a commercial CFD package, Fluent. The working fluid is distilled water. The effects of the inclination angle, phi and the Rayleigh number, Ra on fluid flow and heat transfer are investigated for the range of angle of inclination between 0 degrees <= phi <= 360 degrees, and Ra from 10(5) to 10(7). It is disclosed that heat transfer changes dramatically according to the inclination angle which affects convection currents inside, i.e. flow physics inside. A fairly good agreement is observed between the experimental and numerical results. (C) 2011 Elsevier Inc. All rights reserved.