In this study the fungicidal activity, expressed as relative inhibition rate, was correlated with trifluoromethyl-1,2,4-triazole derivative descriptors by the Partial Least Squares (PLS) method. For a data set containing 18 structures, previously modeled by the RM1 semiempirical quantum chemical method, various electronic and 0D, 1D, 2D and 3D descriptors were calculated. The test set includes five out of the eighteen Mannich bases containing trifluoromethyl-1,2,4-triazoles. The resultant two-components PLS model had acceptable statistical quality (R²X(Cum) = 0.805, R²Y(cum) = 0.823 and Q²(Cum) = 0.735) for predicting the fungicidal activity of the 1,2,4-triazole derivatives. Specific 1,2,4-triazole structural features supplying information about interatomic distances, topological distances, types of atoms and which encode chemical information influence the fungicidal activity.