In vitro cytotoxicity and inflammatory response following exposure to nanoparticles (NPs) made of poly(lactide-co-glycolide) (PLGA) have been investigated on A549 human lung epithelial cells. Three different PLGA NPs (230 nm) were obtained using different stabilizers (polyvinyl alcohol, chitosan, or Pluronic(®) F68) to form respectively neutral, positively or negatively charged NPs. Polystyrene NPs were used as polymeric but non-biodegradable NPs, and titanium dioxide (anatase and rutile) as inorganic NPs, for comparison. Cytotoxicity was evaluated through mitochondrial activity as well as membrane integrity (lactate dehydrogenase release, trypan blue exclusion, propidium iodide staining). The cytotoxicity of PLGA-based and polystyrene NPs was lower or equivalent to the one observed after exposure to titanium dioxide NPs. The inflammatory response, evaluated through the release of the IL-6, IL-8, MCP-1, TNF-α cytokines, was low for all NPs. However, some differences were observed, especially for negative PLGA NPs that led to a higher inflammatory response, which can be correlated to a higher uptake of these NPs. Taken together, these results show that both coating of PLGA NPs and the nature of the core play a key role in cell response.