A method is presented by which chloramphenicol clearance (CI) can be estimated from a single serum sample obtained 6 hours after the initial intravenous dose. The method was evaluated prospectively in 20 infants and children who received intravenous chloramphenicol sodium succinate. Agreement between predicted and observed clearance was excellent (r = 0.914, p < 0.001). The equation of the observed regression line was: observed = 0.886x predicted + 0.019. The method appears to provide reasonably accurate estimates of clearance which can be used for rapid clinical adjustment of dose.