The objective of this study is to investigate the effects of carbonic agent and nanoclay loading level on the properties of the added flame retardant and plasticized polylactic acid (PLA) composites. Pentaerythritol (PER) was used as a carbonic agent in the composites. The flammability behaviour of these composites was investigated with the increasing nanoclay loading level. Flame retardant properties of plasticized PLA composites, which consist of PER and nanoclay as a synergistic agent, were evaluated. While the nanoclay loading levels were changed between 1-5 wt% of these samples, PER loading levels were fixed at 2 wt%. Besides, effects of increased PER loading level were also investigated with 3 wt% clay loading. Samples were produced by extrusion and injection molding techniques. The morphological, thermal, and mechanical properties were studied. The flammability was evaluated by Limiting Oxygen Index (LOI) and vertical burning test (UL-94). The results showed that the increased PER level did not significantly change LOI values of the PLA-based nanocomposites. In addition, the highest LOI value was observed as 32 for 1 wt% nanoclay including a sample. While adding PER to the PLA/PEG/TPP increased the elongation at break value, addition of the nanoclay decreased this value for nanocomposites. (c) 2017 Sharif University of Technology. All rights reserved.