The ability to conjugate drugs with quantum dots (QDs) offers excellent prospects in pharmacotherapy for the improvement of diagnosis and treatment of human diseases. Here, we report a facile strategy to prepare dual-functional nanomaterials consisting of QDs and an anticancer drug. Hydrophilic AgInS2/ZnS QDs were obtained through an ultrasonication process by introducing the amphiphilic polymer, poly(maleic anhydride-alt-1-octadecene) (PMAO). Subsequently, the anticancer drug methotrexate (MTX) was covalently coupled to the surface of the AgInS2/ZnS QDs by carbodiimide chemistry. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay indicated that these hydrophilic PMAO-coated AgInS2/ZnS QDs exhibited negligible cytotoxicity. Human cervical (HeLa) cancer cells had >80% cell viability after 24h at concentrations of up to 300μg/mL. Confocal laser scanning microscopy revealed that the AgInS2/ZnS QDs conjugated with MTX were taken up effectively by HeLa cells. In addition, this nanomaterial was shown to have a dose-dependent antiproliferative effect in cancer cells by the MTT assay. These important features suggest that AgInS2/ZnS QDs conjugated with MTX might be a novel candidate for cancer therapeutics and diagnosis in future.