The thermal decomposition behavior of polylactide fabrics treated with tetrabromobisphenol A (TBP-A) or triphenylphosphate (TPP) in suspension was studied by thermogravimetry (TG) and differential thermal analysis (DTA). The TG analysis showed that the thermal decomposition of a TBP-A-treated sample with the limiting oxygen index (LOI) of 25.9 and 4.98wt/wt% of TBP-A was accelerated both under nitrogen and under air. When this sample was heated under air, the exothermic reaction was retarded in comparison with the untreated sample. The amount of remained char of the sample was larger than that of the untreated. The sorbed TBP-A was considered to lead the thermal decomposition of polylactide through a mechanism different from that of the untreated polylactide. The TG curve of a TPP-treated sample with LOI of 27.8 and 2.96wt/wt% measured under nitrogen was similar to that of the untreated sample. The weight loss of the treated sample was higher than that of the untreated below 374°C and became considerably lower above the temperature, when measured under air. The kinetic study was made under nitrogen based on the TG data measured at different heating rates. Almost all of the sorbed TPP seemed to be decomposed by the same mechanism to that of free TPP and to be removed from the sample.