In this study, different organoclays (OMMTs) were prepared using various fatty nitrogen compounds (FNCs) and natural clay, sodium montmorillonite (MMT). The clay modification was carried out by stirring the clay particles in an aqueous solution of fatty amides (FA), fatty hydroxamic acids (FHA), and carbonyl difatty amides (CDFA). These OMMTs were then used for nanocomposites production to improve the property balance of poly(lactic acid) (PLA) by solution casting process. All sets of OMMTs and nanocomposites were characterized using various apparatuses. In the nanocomposites, where the clay surface is pretreated with FA, FHA and CDFA, the basal spacing of the clay increased to 2.94, 3.26 and 3.80 nm, respectively The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results confirmed the production of nanocomposites. PLA modified clay nanocomposites show higher thermal stability and significant improvement of mechanical properties in comparison with pure PLA.