Young children have a natural tendency to mouth items to explore their environment. Mouthing carries mechanical and chemical hazard potential for injury to the child, for example if they swallow an item they may choke, they may cut themselves on sharp items, and certain chemicals are present in plastic items which may pose a risk to children. Few data are available on the time that young children mouth items, how they mouth, and what they mouth. This study gathered data on 236 children aged between 1 month and 5 years to supplement and extend existing data. Findings are presented of estimated average and maximum daily mouthing times for children, how they mouth, what they mouth, and whether the items mouthed were intended to be. A validation study was carried out to determine the accuracy of the parental observation method used to gather the data. The implications of the findings of this study are discussed with respect to reducing the potential for mechanical accidents in the home.