The objective of this study was to analyse the influence of introducing Schweres Warmblut (SchW) blood on the zoometric features of Silesian breed horses. The research material was pure Silesian breed horses and crossbreeds with the SchW breed, born in the period of 1984–2004. The population was divided into four groups, depending on the contribution of Schweres Warmblut blood (0.0%, 0.1–24.9%, 25.0–49.9% and 50% and more). Differences were determined among groups in the range of values of the three basic characteristics (height at withers, chest and cannon circumferences), build indices (massiveness, boniness and strength), and point-scale estimation. The highest differences between Silesian horses and F₁ generation crossbreeds were observed in height at withers (stallions: 161.04 and 165.13 cm, mares: 159.58 and 162.45 cm), massiveness index (stallions:124.56 and 120.19), and point-scale estimation (mares: 77.0 and 79.61 points, respectively). The groups with lower shares of SchW blood were characterized by intermediate values that corresponded more to changes that took place in the Silesian breed over time, than to those resulting from the contribution of SchW blood.