Paclitaxel (PTX) is a potent anticancer drug. In the present study, PTX was loaded in poly-3-hydroxybutyrate-co-3-hydroxyvalarate (PHBV) to fabricate the PTX/PHBV (drug-loaded) nanoparticles via the nanoprecipitation method. Blank PHBV nanoparticles were also prepared. The drug-encapsulation efficiency of PTX/PHBV nanoparticles was 45±0.4%. The PTX/PHBV nanoparticles exhibited a pH-sensitive release profile and followed a quasi-Fickian diffusion mechanism. Cytotoxic properties of PHBV and PTX/PHBV nanoparticles were checked against the MCF-7 and Caco-2 cell lines. The PHBV nanoparticle did not inhibit the proliferation of MCF-7 and Caco-2 cell lines, thus depicting their non-toxic and biocompatible nature. On the other hand, the PTX/PHBV nanoparticles demonstrated 1.03-fold higher cytotoxicity and 1.61-fold enhanced apoptosis after treatment with the PTX/PHBV nanoparticles versus free PTX. In summary, the PHBV nanoparticles could be a potential candidate for the delivery of PTX for cancer treatment.