Abstract Nanomaterials have widely been used in the field of biological and biomedicine, such as tissue imaging, diagnosis and cancer therapy. The aim of this study is to investigate cytotoxicity and photodynamic effect of combined application of polyvinyl pyrrolidone (PVP) modified ZnO nanorods with anticancer drug daunorubicin (DNR) in photodynamic therapy (PDT). Daunorubicin (DNR) has a broad spectrum of anticancer activity, but it is limited in clinical application due to its serious side effects. In DNR-ZnO/PVP nanocomposites, ZnO/PVP nanorods act as drug carrier of DNR in drug delivery system (DNR-ZnO/PVP nanocomposites). This drug delivery system induced remarkable improvement in anticancer activity, as demonstrated by MTT assay using 3-(4,5-dimethylthiazol-2yl)-2,5 diphenyl tetrazolium bromide (MTT reagent). This has been also demonstrated by antibacterial activity and DNA cleavage study. The findings suggest that DNR delivery strategy is a promising approach to cancer therapy.