Cancer is still an unsolved problem, although many advances have been attained in developing effective anticancer drugs. A serious challenge in front of scientists is delivering the drugs to cancer cells in an effectual lasting amount, the bioavailability. Regarding hydrophobic drugs, this problem becomes dramatically worse and it raises the necessity of the existence of a delivering vehicle. Nanoparticles have met this demand satisfactorily and have shown notable potential in delivering the therapeutic agents. In order to examine the antiproliferative effect of nanoparticle-encapsulated curcumin, which is a well-known hydrophobic anticancer agent, we used PAMAM dendrimer to deliver the curcumin to breast cancer cell lines. Measuring telomerase activity in treated cells revealed that dendrimers played their delivering role efficiently, without introducing any unwanted effect. Therefore, they could be considered as well-suited carriers for curcumin.