There are increasing numbers of developed nanocarriers for anticancer drug delivery in the aim to avoid side effects of the conventional chemotherapy. Filomicelles with folic acid (FA) as a targeting moiety are a novel approach that can potentially maximize therapeutic efficacy while minimizing side effects. The aim of this study was to analyze the influence of composition of PLA-based micelles functionalized with folic acid on their drug encapsulation and release properties as well as cytotoxic activity against cancer cells. Micelles were obtained from combination of poly (L-lactide)-Jeffamine-folic acid (PLA-Jeff-FA) and poly (L-lactide)-poly (ethylene glycol) (PLA-PEG) or poly (L-lactide)-poly (ethylene glycol)-folic acid and PLA-PEG. E− 29-diethoxyphosphoryl-28-O-propynoylbetulin as an anticancer agent was encapsulated into micelles. The in vitro biocompatibility of drugfree micelles was confirmed as well as cytotoxicity of E− 29-diethoxyphosphoryl-28-O-propynoylbetulin loaded micelles against FR-positive SK-BR-3 cells. The micelles provided a release of an active agent for over 260 h. However, the micelles characterized differences in morphology, drug loading and release properties. The hydrophobic block length has been identified as a factor that may be used to control inter-and intramolecular interactions and, in consequence, micelle's properties, e.g. drug encapsulation efficiency and release rate.