This paper presents a correlation found between the surface roughness and critical surface tension of wetting of calcite and barite minerals. The minerals were ground in ball, rod and autogenous mills to collect samples for further tests (i.e. roughness and wettability). The surface roughness values of those minerals were determined on the pelleted surfaces of the ground powders by employing Surtronic 3(+) roughness-meter instrument. The contact angle measurements were also made by a goniometer on these pellets in order to determine the critical surface tension of wetting of calcite and barite minerals. From the experimental work, it is stated that the wettability degree of calcite and barite minerals increase with their increasing surface roughness. The relationships could be stated as: gamma(c) = aR(a) + b type of equations; where gamma(c) is the critical surface tension of wetting, R. is the surface roughness measured, a is the slope and b is the intercept of the regression line. (C) 2003 Elsevier B.V. All rights reserved.