Background and Objective: The importance of β-adrenergic signals in bone formation and resorption has been well investigated. However, little is known about the role of β -adrenergic signals in osteoblastic differentiation of mesenchymal stem cells (MSCs), which is critically important in bone physiology and pharmacology. In this study, RUNX2 and Osteocalcin gene expression were quantified in MSCs differentiated by osteoblastic differentiation medium (ODM) and Isoproterenol (ISO). Materials and Methods: In this experimental study, human mesenchymal stem cells were treated by osteoblastic differentiation medium and ISO. RNA extraction was carried out from both osteoblastic differentiation medium at 4 and 21 days of differentiation and from undifferentiated MSCs. RUNX2 and osteocalcin gene expression were quantified by quantitative Real Time-PCR. Results: Isoproterenol decreased the expression of RUNX2 and osteocalcin genes at 4 and 21 days of osteoblastic differentiation. 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