Propolis is a resinous substance which is used by bees to repair and maintain their hives. It has more than 180 compounds including flavonoids, phenolic acids and its esters which have anti-inflammatory, antibacterial, antiviral, immunomodulatory, antioxidant and antiproliferative effects. Propolis is shown to inhibit cell division and protein synthesis. However the exact mechanism underlying antitumor effect is not clearly described. On the other hand progressive telomere shortening to a critical level results with senescence of normal cells by inducing apoptosis and telomerase prevents erosion of telomeres. In this study we aimed to evaluate hTERT ratios in propolis-treated T-cell acute lymphoblastic leukemia (CCFR-CEM) cell line. Cell counts and cell viability of propolis-treated and propolis-free T-cell acute lymphoblastic leukemia (CCFR-CEM) cell line were assessed by trypan blue dye exclusion test and MTT assay. The LightCycler instrument was used (online real-time PCR) for the quantification of hTERT in CCFR-CEM cell line. The hTERT ratio significantly decreased 60 and 93% after 24 and 72 h respectively compared to the initial value of the cells incubated with propolis. It had almost no cytotoxic effect and caused 30, 30, 22 and 12% decrease in cell counts after 24, 48, 72 and 96 h respectively which is statistically significant.