Unlike previous research on soft and clay-bearing rocks, this study seeks to investigate the effect of wetting and drying (W–D) cycles on the engineering properties of two hard rocks. A series of W–D cycles were applied to fresh specimens of greywacke and basalt, and their strength, slake durability and density were progressively assessed as the number of cycles increased. It was found that unlike the basalt, the strength of greywacke rapidly decreased with increasing W–D cycles while the rock density and slake durability index remained almost the same. Analysis of the crack propagation in both rocks revealed that, compared to soft and clay-bearing material, the process of strength degradation in hard rocks was rather different, with a more pronounced effect of crack development. In addition, comparisons with the data obtained for the same type of rocks yet naturally weathered was performed to establish similarities between the properties of laboratory-deteriorated and naturally weathered rocks. The obtained results are expected to provide more practical values for such laboratory studies where the rate of rock deterioration is relatively high (several weeks) in comparison to what is commonly observed in the field (several years).