Silibinin possesses a broad spectrum of biological applications such as anticancer activities; however, poor bioavailability reduces its efficacy at the tumour sites. In the current study, silibinin was encapsulated in nanoniosomal particles in the presence of polyethylene glycol and estimated its efficacy against breast cancer in vitro. Nanoniosomalsilibinin was synthesized using the reverse phase evaporation method and characterized for shape morphology, particle size, zeta potential and drug-release characterises. In the next step, MCF 10A breast cell lines were used to evaluate the rate of nanoniosomalsilibinin cytotoxicity. In these investigation, the particle size and zeta potential of the niosomal nanoparticles were calculated 322.3±17.6nm and -18.4±1.1mV, respectively. Drug loading and encapsulation efficiency were evaluated 92.8±7.3 and 14.3±1.3, respectively. The drug release study confirmed the power of nanoparticles to drug retention by 64.1± 5.9 release in a period of 34 hours. MTT assay revealed higher cytotoxic efficacy of silibininnanoniosomal particle than free silibinin on MCF 10A cell lines. Taking collectively, the present study suggests that silibinin-loaded nanoniosomes can be applied as an effective drug delivery system to cause a usefully chemopreventive response in order to the treatment of breast cancer.