Polystyrene nanoparticles (PS NPs) are biocompatible and low toxic material to biological systems. In this mind, PS NPs are widely used as a model for studying the interaction between nanoparticles and cells. Even PS NPs showed low toxicity, they could affect to some cellular responses. In this study, we investigated the influence of PS NPs on the epidermal growth factor (EGF)-response in the A431 human epithelial carcinoma cell line. The results showed that PS NPs interfered with the normal EGF-response of A431 cells in a dose-dependent manner. In addition, EGF significantly increased the uptake of PS NPs in A431 cells. Localization studies of PS NPs and EGF receptor (EGFR) indicated that changes in the EGF-response of A431 cells are related to the interaction between PS NPs and the EGF-EGFR complexes. The viability of cells exposed to PS NPs or combination of PS NPs and EGF decreased due to PS NPs induced cell death. The results also suggested that without EGF, PS NPs internalized in the cells cause cell death by necrosis, whereas EGF enhances the uptake ratio of PS NPs, and PS NPs in the cytoplasm together with EGF-EGFR complexes may inhibit receptors recycling, leading to apoptosis. This finding could be useful for the safe and effective use of nanoparticles in clinical applications.