The presence of antibiotics in foods of animal origin may be due to the mixing of antibiotics from different feeds in order to stimulate growth and improve yield, use for prophylactic or therapeutic purposes, and of course the accidental incorporation of antibiotics into various products. Antibiotics are used in animal husbandry in small quantities to ensure a superior use of feed, guaranteeing a saving of about 5% and a weight gain of about 10%. Identification of antibiotic residues in food of animal origin presence of toxicological interest, as it causes primary and secondary effects on the health of consumers. In terms of effectiveness, the antibiotics can be 1000 times more active than any other preserving agent. By reason of antibiotics effect is mainly bacteriostatic, for the preservation of food it is necessary that the antibiotic is permanently present in the product, its stability over time being an essential condition. Antibiotics have a selective action. Antibiotics used as food additives must meet certain characteristics such as: not being related to antibiotics used in human therapy and having little or no absorption after administration. Also these preparations do not must have an impact on the environment or this impact need be reduced. Sulfadimethoxine, sulfamethoxazole, sulfaquinoxaline and sulfadiazines are the most widely used sulfonamides in veterinary medicine. If the waiting period is not met, products of animal origin may be contaminated with residues of these substances. The interest in detecting these residues is very current. The first, the largest exceedance of the legal level of sulfonamides in tissues was reported in the USA in 1970. In the last 25 years, sulfonamides have produced more overtaking of the maximum permitted limit of residues than any other group, with the highest incidence in pigs, followed by cattle and birds. Actually, exceeding the maximum residues limit for sulfonamides is common for all the world. Since 2015, the European Center for Prevention and Control and the European Food Safety Agency have published annually the results of research on antimicrobial resistance from all countries of the European Union. In the Republic of Moldova, the problem of the presence of antibiotics in the environment, including food, is little researched, but is a great interest for both research and state institutions.