Molecularly targeted therapy emerged as a novel therapeutic strategy in the treatment of multiple cancers. In the present study, we have developed gemcitabine (GEM)-loaded cetuximab (CET) surface modified poly(lactic) acid (PLA) nanoparticles (NP) (CET-GEM/PLA NP) to target to epidermal growth factor receptor (EGFR) overexpressing non-small cell lung cancer (A549) cells. The resultant CET-GEM/PLA NP showed a very uniform particle size of∼120 nm and spherical morphology. It exhibited a pH-dependent controlled release pattern. A sustained release of drug in the physiological conditions and faster release in tumor pH will greatly improve the chemotherapeutic efficiency of therapeutic system. Higher or enhanced cellular uptake of CET-GEM/PLA NP in A549 cancer cells clearly indicates the EGFR-mediated receptor based active targeting. Nearly, a two-fold increase in fluorescent intensity was observed for CET-GEM/PLA NP comparing to that of non-targeted NP in the cancer cells. EGFR-mediated internalization of the targeted NP was further confirmed by the confocal microscopy. MTT assay clearly showed the enhanced cell killing effect of CET-conjugated NP due to the selective delivery of GEM to the EGFR over expressing cancer cells. Finally, comparing to the non-targeted NP, CET-GEM/PLA NP showed greater level of cell apoptosis (early and late apoptosis∼40%). Our results showed that antibody conjugation on the surface of NP could be a potential treatment strategy for EGFR over expressing cancer cells. This suggests that CET-GEM/PLA NP could be potentially used for the treatment of NSCLC (lung cancers).