In the present work the aerodynamic characteristics of a bus was studied. Flow analysis was carried out assuming two dimensional, steady incompressible and viscous. The effect of speed and yaw angle variation were investigated separately. Experimental and theoretical investigations were carried out. A bus model of 1:20 scale ratio was used for experimental testes. The tests were carried out in a low speed wind tunnel, the air speed was varied from 14.5 m/s to 24.5 m/s and yaw angle from 0o to 15.A package program (Ansys 5.4) was used to carry out the theoretical study. This gave a good ability to calculate the pressure and velocity distribution and sketching the eddies in the near wake behind the bus model. It was found that increasing the yaw angle increases the drag and pressure coefficients. The difference in the pressure coefficient in the flow direction CP(front-rear) varies from 0.05 at Q=0o to -0.055 at Q=10o, when air speed equals to 14.5 m/s .For the same condition the drag coefficient varies from 0.72 to 0.76.The comparison made between the experimental results, and some experimental published data showed a good agreement. The results obtained by Ansys 5.4 program for the specific configuration were compared with the present experimental work and they showed a reasonable agreement .