The wettability of finely divided solids (powders and agglomerates) plays an important role in a number of practical applications such as dissolution, dispersion, granulation, coating, drying, etc. However, the characterisation of this property for powder materials is not a trivial task and has motivated several investigators to develop a large variety of experimental methods to assess it through its inherent parameter, the solid-liquid contact angle. The objective of this paper is to present and discuss the existing methods used in the wettability assessment of finely processed solids, specially, as the hydrophobicity assessment techniques are concerned. (c) 2005 Elsevier B.V. All rights reserved.