ABSTRACT. Quantitative structure-activity relationship (QSAR) analysis for recently synthesized imidazole-(benz)azole and imidazole -piperazine derivatives was studied for their anticancer activities against breast (MCF-7) cell lines. The statistically significant 2D-QSAR models (r 2 = 0.8901; q 2 = 0.8130; F test = 36.4635; r 2 se = 0.1696; q 2 se = 0.12212; pred_r 2 = 0.4229; pred_r 2 se = 0.4606 and r 2 = 0.8763; q 2 = 0.7617; F test = 31.8737; r 2 se = 0.1951; q 2 se = 0.2708; pred_r 2 = 0.4386; pred_r 2 se = 0.3950) were developed using molecular design suite (VLifeMDS 4.2). The study was performed with 18 compounds (data set) using random selection and manual selection methods used for the division of the data set into training and test set. Multiple linear regression (MLR) methodology with stepwise (SW) forward-backward variable selection method was used for building the QSAR models. The results of the 2D-QSAR models were further compared with 3D-QSAR models generated by kNN-MFA, (k-Nearest Neighbor Molecular Field Analysis) investigating the substitutional requirements for the favorable anticancer activity. The results derived may be useful in further designing novel imidazole-(benz)azole and imidazole-piperazine derivatives against breast (MCF-7) cell lines prior to synthesis.