Depletion of chloramphenicol (CAP) in muscle of rainbow trout was evaluated following 4 days of oral administration with two dosages (42 and 84 mg/kg/day). Sampling was conducted during treatment and for 35 days following the end of treatment. Analysis was carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Concentrations observed during treatment were more than 300 μg/kg. A significant elimination occurred within 9 days after the cessation of treatment in both groups. Higher CAP levels were measured in the group treated with higher dose. CAP was not detectable after 13 and 15 after the end of treatment in both groups.