Skidding by heavy forestry machinery can affect soil physical properties. We assessed the effects of ground-based skidding on soil bulk density and total porosity in a southern Italian forest. Treatments included a combination of four levels of traffic intensity (1, 5, 10, and 15 passes) of a John Deere 548H rubber skidder and two levels of slope (< 20% and > 20%). Further, soil bulk density and total porosity were evaluated at different distances from the track (BT). The results 1096 A.R. Proto et al. indicated soil bulk density increased with traffic frequency, while soil total porosity decreased. Further, slope steepness did not affect soil physical properties but interacted with the number of passes to affect soil total porosity. The critical value for this parameter occurred after 15 passes on a < 20% slope and six machine passes on a > 20% slope. The statistically significant impacts of the skidder on soil physical properties were evident at distances of up to 2 m from each side of the skidding trail. The latter finding suggests special attention should be taken during the skidding operations to minimize the adverse effects of groundbased skidding on soil physical properties.