AIMS: The present study aimed to develop and characterize poly (ɛ-caprolactone) (PCL) based lipid polymer hybrid nanoparticles for sustained delivery and in-vitro anti-cancer activity in MCF-7 and HeLa cells cancer cell line. MATERIALS AND METHODS: The nanoprecipitation method was used for the development of 5-fluorouracil loaded lipid polymer hybrid nanoparticles (LPHNPs). The developed LPHNPs were characterized for physicochemical characteristics and the anti-cancer effect was evaluated in MCF-7 and HeLa cells. SIGNIFICANT FINDINGS: Six formulations having fixed amount of drug and varied lipid, polymer and emulsifier concentrations were prepared. The particle size was in the range of 174 ± 4 to 267 ± 2.65 nm, entrapment efficiency (92.87 ± 0.594 to 94.13 ± 0.772%), negative zeta potential, optimum polydispersity index and spherical shape. FTIR analysis shows no chemical interaction among the formulation components, DSC analysis reveals the disappearance of 5-FU melting endotherm in the developed LPHNPs suggesting amorphization of 5-FU in the developed system, XRD analysis indicates successful encapsulation of the drug in the lipid polymer matrix. The in-vitro release shows a biphasic release pattern with an initial burst release followed by a sustained release profile for 72 h. The drug loaded LPHNPs exhibited a greater cytotoxic effect than 5-FU solution due to sustained release and increased cellular internalization. The acute toxicity study revealed the safety of the developed carrier system for potential delivery of chemotherapeutic agents. SIGNIFICANCE: The developed LPHNPs of 5-fluorouracil will provide the sustained release behavior of 5-fluorouracil to maximize the therapeutic efficacy and minimize the dose related toxicity.