Introduction: Fats are present in our diet every day. It is important for us that we can properly harmonize the relationship between the fats that protect our health and those that harm us. The latter include trans fatty acids, which have a proven negative effect on health. Aim: The purpose of the diploma work is to present the impact of trans fatty acids on health. We want to present where trans fatty acids are present in the diet and which are the most common foods with it. The purpose of the work is also to review the legislation in the field of food industry, where trans fatty acids are discussed and the consequences of excessive use of them are presented. Method: The method of work is descriptive. A critical review of professional and scientific domestic and foreign literature is used. The used databases are CINAHL, EBSCOhost, MedLine, archive of Health Care Review and the Official Gazette of the Republic of Slovenia. Discussion and conclusion: After reviewing the literature, we found out the negative consequences of the excessive use of TFA in everyday diet. They cause cardiovascular disease, impair the cognitive function of an individual, increase LDL cholesterol, and raise systolic blood pressure. It is recommended to establish a preventive activity in the field of nutritional counseling and a consistent use of legislation that requires the labeling of trans fatty acids on foods.