The turbulent outward fluid flow between stationary and a rotating disc enclosed by a cylindrical housing has been investigated experimentally . This type of flow occurs in many applications of engineering interests . Most of the flows enco-untered in practice are turbulent specially in turbo-machinery. The effect of surface roughness on the friet.ional voment of the rotating disc as well as on the radial pressure distributi-ons has been investigated for different relative roughness ratios of the rotating disc CR/k),16005CR/k35I6401 . Here k is the mean particle diameter of the used grain size and R is the outer disc radius . The flow is investigated at a dimensionless gap height CID of 10.013 SCHmh/10.15 0.401, mass flow coefficient CCw er 11.0x103 5CCwapWeR35 4.2x103 and rotational Reynolds number (Re) of 13x1055 (Re•peR2/0)5. 1.21x 1061. Radial pressure and frictional moment for rough discs are compared with the experimental results obtained on smooth rotating discs . The results have showed that the surface roughness affects strongly upon the radial pressure distribution, the frictional moment and the axial thrust force .