The Lidcombe Program of early stuttering intervention is a parent-delivered behavioural treatment. This project investigates the relation between time since onset of stuttering and the duration of treatment with the Lidcombe Program. In the past, time since onset has been associated with duration of treatment, and these findings are important for deciding whether to begin treatment or to delay treatment to give a chance for natural recovery to occur. However, these studies relied on retrospective methods. The present project incorporates prospective methods, and preliminary data are presented.