HPMA copolymers are one of the most promising drug carriers as their biophysical and biochemical properties, including their immunocompatibility, are very favorable. So far, there is no evidence that HPMA copolymers can interact with the immune system in a way that would lead either to suppression of some of its crucial functions or to inappropriate activation with possible serious side-effects and thus we can conclude that HPMA copolymers are convincingly proved to be "immunologically" safe. Moreover, it was shown both in mice and humans that HPMA copolymer-bound doxorubicin (DOX-HPMA) conjugates possess besides powerful anti-tumor effect also various immunomodulatory properties and exert significantly decreased side-toxicities, minimized bone marrow toxicity and cardiotoxicity being the most important ones. The possibility to induce potent and long-lasting tumor-specific immunity during the treatment with these compounds which is capable to provide protection against minimal residual disease is one of the most important and therapeutically valuable features of these conjugates.