Introduction: Β-AR receptors are one of the proteins involved in cancer and stress. The therapeutic activity of β-blockers such as propranolol is attributed to the blockade of β1-adrenergic receptors (ARs). In this study, the effect of propranolol on the viability of K562 cell line was examined. Material and methods: In order to assessment of anti-tumoral effects of propranolol, different concentrations of propranolol were prepared. K562 cells were treated with different concentrations of propranolol, then the percentage of inhibitory effect of propranolol on K562 cell viability at different times (24, 48 and 72 hours) was estimated by MTT assay. Gel electrophoresis of DNA and DAPI staining were used for apoptosis investigation. Statistical comparisons were performed using two-sample t-test, Nominal significance level of each univariate test was 0.05. Results: Propranolol decreased viability of K562 cell line. The inhibitory effect of propranolol is time- and concentration-dependent, thus in higher concentrations and 72 hours after treatment, the maximum inhibitory effect was observed. (P<0.05). As the results showed, Propranolol induces apoptosis in K562 cell line. Conclusions: With respect to the inhibitory effect of propranolol on cell viability and its apoptotic effect on K562 cell line, this drug may be used for cancer therapy.