Tractor traffic as a cause of soil compaction is widely recognized as one of the most important factors responsible for environmental degradation and plant yield losses. It is a serious problem for perennial crops, where the soil surface is wheeled without any opening operation. The aim of our study was to evaluate the effect of tractor traffic on meadow fescue (Festuca pratensis) yields and root development. The field experiment was located in Mydlniki near Kraków, Poland, on silty loam Mollic Fluvisol. Experimental plots were established in randomized block design with four replications. Four compaction treatments were applied using the following range of number of passes: (P0) untreated control, (P2) two passes, (P4) four passes and (P6) six passes completely covering plot surfaces after each harvest. The dry matter (DM) of the yield and roots (RMD) were determined. Morphometric parameters of roots were estimated using image analysis software. Root length density (RLD), specific root length (SRL), and mean diameter (MD) were calculated. Tractor traffic resulted in significant influence on meadow fescue annual yields. The highest annual yields were obtained at the P2 and P4 treatments. However, in the first cut it was noticed that an increase in the number of passes increased plant yields. During the second and the third cut it was found that intensive tractor traffic decreased plant yields, probably as an effect of damage caused to above-ground parts of plants. The meadow fescue roots were significantly affected by tractor traffic only in the 5-15 cm soil layer. Tractor traffic increased the RLD value in a root diameter range of 0.1-0.5 mm. However, any other morphometric parameters, like mean root diameter (MD), specific root length (SRL) or dry root diameter (RDM) were not affected by soil compaction.