It should be recognized that children are not small adults, hence dosing in children should not be a 'small adult dose'. A mean population dose in all age groups is just an average dose and not necessarily the best or the correct dose for a given patient. The dose of a drug varies from patient to patient and individual adjustment of the dose is always ideal but is not always practical. Theoretically, dose selection in paediatric drug development or clinical settings can be done by using either body weight or the clearance of a drug. Over the years, a lot of approaches have been suggested for the prediction of drug clearance or dose in paediatrics. Although some proposed methods are useful for the prediction of clearance or dose in children, there remains a high degree of uncertainty in the prediction of drug clearance or dose in children. In particular, the prediction of clearance or dose in an individual patient remains highly erratic. This review takes a critical look at these approaches and highlights the application and limitations of these proposed methods.