QSAR can modify the molecular structures for achieving the desired molecule with the proposed property, without experimental measurement. In the current study, we extend a published work that had been investiged the caffeic acid derivatives as antibacterial and antifungal agents. In this report, QSAR and regression analysis were used to predicate the antimicrobial activity of these derivatives. Moreover, the antimicrobial activity for these molecules that was obtained experimentally is compared with the calculated ones. The antimicrobial activity of some of newly postulated caffeic acid derivatives showed a pronounced antimicrobial activity. QSAR and regression equations were useful in predicating the biologic activity of the old and postulated molecules with good validity.