The administration of antibiotics by salmon farms in Chile, facilitates the accumulation in the marine environment, affecting the biota. In 2016, 382 tons of antibiotics (oxytetracycline and fl orfenicol) were used. In this study, the biological activity of florfenicol and oxytetracycline in larvae of Drosophila melanogaster Meigen, was evaluated under laboratory conditions. A completely randomized experimental design was applied in the bioassays with 10 treatments (0.3, 0.6 and 1.2 mg/mL of florfenicol and 0.3, 0.6, 0.8, 1.2, 1.6 and 3.2 mg/mL of oxytetracycline) applied to the parental generation, with two repetitions. Mortality, effects on the life cycle, substrate analysis and observation of organisms in the parental generation, and in two successive generations were evaluated. The results indicate that the higher the concentration of antibiotic applied to the parental generation, the mortality increases in the first generation and the life cycles are delayed in the following generations; in addition, it increases the frequency of appearance of adults with morphological alterations of the wing; the food substrate changes the color and pH in all treatments. Both antimicrobials have adverse effects on the development of Drosophila melanogaster and on the culture medium. The effect of antibiotics on the parental generation is inheritable, in two successive generations, that had decrease in the number of offspring and individuals with deformed or absent wings. Antibiotics would directly affect the wildlife surrounding the salmon farming centers, which should be controlled to avoid significant environmental damage.