Young children's slips of the tongue are a rich source of information about developing language processing and storage mechanisms. This paper presents an analysis of 907 slips from 32 children, ages 1;4–6;0, collected in naturalistic settings. It is found that these children make most of the same types and proportions of slips as adults: phonological errors outnumber lexical, which exceed phrasal. In phonological errors, anticipations are most common, followed by perseverations and exchanges; children make more completed anticipations and exchanges than adults, probably due to less mature self-monitoring. Like adults, children make more substitutions than additions or omissions. Children's slips support a theory of speech planning in which propositional, syntactic, intonational, content word, function word and phonological levels have somewhat independent status; however, there is little evidence for a derivational morphology level at this age.