Polylactic acid (PLA) based nanocomposites with waxy maize starch nanocrystals (WSNC) as nanofiller were melt-blended in a Haake Rheomix. WSNC were incorporated into PLA at three different loadings – 1 wt-%, 3 wt-% and 5 wt-% in PLA matrix. The morphological, thermal and crystalline properties of neat PLA and the prepared nanocomposites were investigated by scanning electron microscopy (SEM), thermo gravimetric analysis (TGA) and modulated differential scanning calorimetry (MDSC), respectively, to determine the effects of adding WSNC at different loadings in PLA. The microscopy study shows the effective dispersion of WSNC in PLA at lower loadings (0-3 wt-%) and agglomeration at 5 wt-% of WSNC. The thermal degradation studies confirmed that the nanocomposites and WSNC are very stable and safe to process in the actual processing temperature limits of PLA, 25-220 ºC. MDSC results show that there is no substantial variation in the glass transition temperature and the melting point of the nanocomposites. However, the cold crystallization temperature was reduced with the increase in WSNC loadings. This decline in cold crystallization temperature may be accredited to the nucleation function of WSNC to improve the crystallinity of the PLA matrix or to the greater interaction amongst the filler and the matrix.