Scaffolds have similar functions to the extracellular matrix and are an important component of tissue engineering techniques. Poly(L-lactic acid) (PLLA) is one of the scaffolding materials used in this field. The aim of this study was to investigate the biocompatibility and effect of novel PLLA scaffolds on mesenchymal stem cell (MSC) proliferation. PLLA scaffolds in this study were nanonodular porous membranes which were prepared by phase separation process. Dental pulp-derived MSCs were cultured on nanonodular membrane scaffolds and cell vitality and proliferation was evaluated over a 2-week period using MMT test on days 5, 7, and 9. Also, ultrastructure and adhesion of MSCs to these novel PLLA nanonodular porous membranes using fieldemission-scanning electron microscopy (FE-SEM) was assessed. The biocompatibility of nanonodular membrane scaffolds was good and the cells adhered well to the membrane surface. The viability of MSCs in the samples with the nanonodular membrane scaffolds was significantly higher than the group without the membrane scaffolds. The highest effect of PLLA nanonodular membrane scaffolds on cell vitality was observed on the ninth day and the least effect was observed on the 5th day. Due to its biodegradability and lack of toxicity, PLLA nanonodular membrane scaffolds increased the rate of adhesion and proliferation of MSCs and this process intensified over time.