Abstract: A new method for preparation of samples of thermoplastic used for IR-spectrometric analysis was proposed in this paper. Sample of thermoplactic was heated on the flat surface of a scraper over an alcohol burner until it was softened in a molten state. The sample was then placed on a plateform (made of marble, granite or glass), and pressed with the scraper in an incline position keeping the end of the scraper to have an acute angle with the plateform and to leave a slit between the scraper edge and the plateform surface, and moved quickly backward with the scraper handle. Thus a thin piece of the thermoplastic sample, having its thickness to be equal to the width of slit approximately, was obtained and to be used for IRS analysis. By varying the slit width, sample of various thickness could be prepared. As shown by experimental results, this new method of sample preparation for the thermoplastic was feasible to be used in substitution for the conventional methods of sample preparation.