Despite well-known differences in drug response between children and adults, dosing guidelines for children are usually developed by extrapolating the results from studies in adults. Instead of body weight, insight into the pharmacokinetics and pharmacodynamics of drugs should serve as the basis for dosing in children. In studies into drug dosing in children, the 'population approach' should be chosen to minimize the burden for the child. With a population approach, the covariates that affect the pharmacokinetics and pharmacodynamics of drugs can be identified in a covariate analysis; examples of covariates include body weight, age, degree of illness and genetic factors. Drugs that serve as a model for a specific elimination route provide the basis for individualized dosing guidelines for children.