Abstract: The use of antibiotics in animals cannot be considered independently from their use in human medicine. The problem of selection for antibiotic resistance in animals and then its transmission to man govern current thinking on antibiotic use. Barring some exceptions, the antibiotics used in animals belong to the same families as those used in man. However, quantitatively, the molecules used extensively in man are rarely used in animals and vice versa. Antibiotics can be used in several ways, especially in farms. According to the case, their use can be prophylactic, metaphylactic or therapeutic and planned individually or collectively. The choice of how they are used has different consequences for antibiotic resistance. Antibiotic resistance is influenced by farm conditions and by scientific and economic considerations.