PURPOSE: To examine the occurrence of complex onset pre- and post-treatment in children treated with three different models of phonological therapy. METHODS: Twenty-one subjects with phonological disorder participated in the study, 16 boys and five girls, with ages varying between four years and seven years and eleven months. The children were divided into three groups of seven subjects, according to the therapy models used: Modified Cycles Model, Maximum Opposition Model and ABAB-Withdrawal and Multiple Probes Model. Data from initial and final evaluations of the phonological system were analyzed, regarding the total production of complex onsets and of production of complex onsets with /l/ and /r/. These were classified as: not acquired, from 0 to 39%; partially acquired, from 40 to 69%; and acquired, from 70 to 100%. Statistical analyses were carried out. RESULTS: Regarding the total number of occurences of complex onsets, there was a difference between pre- and post-therapy means of not acquired and acquired complex onsets in the Modified Cycles Model and in the Maximum Opposition Model; in the ABAB-Withdrawal and Multiple Probes Model, this difference was found only for acquired complex onsets. The same was veryfied for complex onsets with /r/. With regards to complex onsets with /l/, differences were found only in the Modified Cycles Model, between not acquired and acquired complex onsets. A different classification of not acquired and acquired complex onsets was observed, in all models, between pre- and post-treatment. CONCLUSION: The three models of phonological therapy were effective for the treatment of complex syllabic onset structure.