QSAR analysis of a series of previously synthesized N-1-arylamino/methyl/ethyl-1,2,4-triazole and N-1-heteroarylamino/methyl/ethyl-1,2,4-triazole derivatives tested for growth inhibitory activity against Bacillus subtilis, was performed using the computer-assisted multiple regression procedure. Using the Hansch and Free Wilson approaches the activity contribution for either the aminomethyl/aminoethyl unit or the aromatic/heteroaromatic ring was determined from the correlation equation.