Drug, gene and protein delivery is a very challenging and exciting area in nanobiotechnology where block copolymers are increasingly considered especially as carriers for chemotherapeutic agents in treatment of various cancers. Cancer chemotherapy is particularly challenging because of nonselective distribution of drugs, associated severe toxicity, multidrug resistance and chronic treatments influencing the quality-adjusted life of patients. These limitations lead to incomplete cure and render many drugs ineffective in treating cancers. Liposomes are currently more advanced in clinical trials and industrial developments but they lack stability and pose difficulties in functionalizing it. More recently, various types of polymer-based nano-constructs have been designed, synthesized and used for the cancer chemotherapy applications. This review discusses the most significant and recent literature developments on specific self-assembled block copolymers as a carrier system such as micelles and vesicles, which can be successfully used to enhance the solubility of hydrophobic drugs, helpful in targeting selective sites in the body, delivering active molecules in a control manner and reducing the side effects, and their role in treatment of cancer.