Individuals with autism spectrum disorders (ASDs) often exhibit well-documented difficulties maintaining skills after they learn them. Acquired skills often disappear from their repertoires. Frequency-building procedures used with other populations have been touted as having special potential relevance for this population, and one of the reported outcomes of training skills to high frequencies includes skill retention. Hence, using frequency-building procedures with individuals with autism may mitigate the retention problems observed in this population. This article presents a data set of skills trained to high frequencies in a clinical setting across a variety of learners with ASDs. Retention data are presented on skills at 1-, 2- or 3-, and 6-month postmastery points, and demonstrate a surprisingly high level of skill retention. The implications of these findings and essential next steps in research are reviewed. (Contains 3 tables.)