Food fraud is not a new phenomenon, however in the recent studies the scale of the problem has been highlighted along with economic losses accompanying it. According to data dated 2018, the fraud in the food branch is estimated, world-wide, to be close to PLN 129 billion. Chocolate comes within the group of cocoa and chocolate  products. In view of the type of raw material it is produced from, it must meet the requirements specified in the  relevant regulations. They include, among others, the conditions under which the lawgiver allows vegetable fat  other than cocoa to be added to those products. The objective of the research study was to identify adulterations of  chocolate with a cocoa fat substitute added on the basis of amounts of fatty acids therein and to assess the value  of stearic-acid-to- palmitic-acid ratio. The experimental material consisted of eight chocolates of various  brands, packed in individual packages, each 100 g of net weight and purchased in retail shops, from different  production batches and bought once a year in the years 2014 – 2018. In total 40 chocolates were tested in the given  period. It was found that the varying quality of cocoa fat available in the market determined the quality of  products manufactured with the use of this raw material. During the research studies, a high variability was  identified of the amount of adulterated products. Significant differences were pointed out in the value of stearicto- palmitic fatty acids ratio between the chocolate samples analysed; furthermore, it was determined that the high- quality cocoa fat made it possible to obtain a sufficiently high proportion ratio even with the addition of a cheaper  cocoa butter replacer.