Most drugs in cancer therapy are associated with serious side effects owing to non-specific cellular uptake of chemotherapeutic drugs by both cancerous and normal cells. Plant extracts are considered for cancer therapy,as they possesshigh antioxidant and anticancer activities. Curcumin (diferuloylmethane), the active ingredientfrom tumeric extract, has gained momentum as a potential cancer drug.It possesseshigh selectivity towards cancer cells while exerting negligible systemic toxicity towards healthy cells,even at higher doses. In this study, curcumin nanoparticles, Cur-NP(28to 200 nm) were engineered as inhalable drug for lung cancer therapy.The effectiveness of Cur-NP to kill lung cancercellswas evaluated using two models lung carcinoma cell lines, A549 and Calu-3. A non-cancerouslung cell line, BEAS-2B,was used as control. In vitro cell study showed that engineeredCur-NPshavehighercytotoxicity effect onlung cancer cell linesA549 and Calu-3,compared to raw curcumin. Thecytotoxicity effect was size-dependent,with the smallest nanoparticles exerting superior activity. Higher cytotoxic effect was further supported by higher internalization of Cur-NPinto these cancer cells. Qualitative results by confocalmicroscopyshowed that Cur-NP (28nm) had higher uptake and internalization, withCur-NPpresent in thenucleus.Interestingly, Cur-NPswere not toxic to normalhealthy cells (BEAS-2B). Inconclusion, Cur-NPshave been demonstrated to besuitable for lung cancer treatment bypulmonary administration.