In the prehistory of western Iran, from the Late Neolithic to the end of the Chalcolithic period, there are some red-slipped potteries that continued to exist with minimal or even without any changes, despite the change in periods and the subsequent change in pottery styles and traditions. This has led to ambiguities and errors in distinguishing these types, and as a result, incorrect identification of the cultural periods of some sites of the Late Neolithic period, especially the Chalcolithic period. Are the red-slipped potteries of the Neolithic period to the end of the Chalcolithic period in western Iran really a special type of pottery that continued to exist without any changes despite the changes of cultural periods? What are the differences between the red-coated potteries of the Neolithic period and the Chalcolithic period? The failure of some researchers to distinguish the Red-Slipped potteries of the Neolithic and Chalcolithic periods creates the assumption that these types of pottery are not mutually exclusive. The present article, using an analytical-comparative method, attempts to answer the questions and hypotheses raised by closely examining the Red-Slipped potteries obtained from the excavations of some significant sites of the Late Neolithic and the Chalcolithic period in the western regions of Iran, such as Siahbid, Genail, Ghazanchi, Saha Chai Tepe, and Tepe Gheshlagh. The results of this research show that although there are undeniable similarities at first glance between the Red-Slipped potteries of the Late Neolithic period to the end of Chalcolithic, there are subtle differences in the form of the pottery, the degree of firing, temper, and the type and color of the coating, which a careful study will help distinguish the pottery of the mentioned periods from each other. The findings of this research show that the Red-Slipped potteries of the Late Neolithic period has burnished slip, a feature that is not seen in the later period, especially in the J and Dalma period. Also, in the late Chalcolithic period, in addition to changes in the color of the pottery’s coating, carved decorations are seen on the outer body of red pottery, which has not been reported for Red-Slipped potteries from previous periods.