Soil structure is the key for controlling soil quality. To assess changes in soil structure and its related indices under different land-use systems, an on-farm investigation was carried out on an Oxisol of Southern Province of Cameroon. Six land-use systems (LUS) consisting of a primary forest, a 30-year old secondary forest, a 25-year old cocoa field, a 15-year old natural fallow, a 3-year old Chromolaena odorata fallow and a 2-month old groundnut (Arachis hypogea) field were tested. Soil samples were collected at 0-5 and 5-10 cm depths and were used to determine particle size distribution (hydrometer method), bulk density and aggregate stability. Soil resistance to penetrometer was measured at the same depths in the field using a hand penetrometer. It was found that the primary forest and the cocoa field were associated with highest clay contents (74.6 and 52.0%, respectively) compared to other LUS. However, bulk density was significantly higher under cocoa field (1.09-1.26 g.cm-3) as compared to primary forest (0.72-0.89 g.cm-3). Soil resistance to penetrometer was the lowest under forests (1.2-5.2 bars) as compared to cropped fields (9-12.5 bars) at 0-5 cm depth. Similar trend was observed at 5-10 cm depth. The proportion of aggregates less than 2 mm in diameter was the least under primary forest (27%) as compared to groundnut field (52%). In contrast, soil aggregates under primary forest and cocoa field were more stable, with the highest mean weight diameter (MWD) of 3.37 and 3.00 mm, respectively.