Background: Estimates of the proportion of children with autism spectrum disorder (ASD) who are minimally verbal vary from 25% to 35%. However, there is a lack of consensus in defining minimally verbal and few detailed reports of communication outcomes for these children following intervention. The aim of this study was to explore how minimally verbal children have been defined and to document the proportion of minimally verbal children in a group of children with ASD receiving a community based early intervention programme. Method: A longitudinal cohort design was used to examine the proportion of children who met criteria for minimally verbal in 246 children with ASD when they entered and exited an early intervention programme. Results: Overall, 26.3% of the children in this study exited the programme using "fewer than five spontaneous and functional words" and 36.4% exited not using "two word phrases" as indicated by direct assessment. However, our findings were mixed depending on measures and definitions used, with parent report indicating that as many as 29.4% of children were not "naming at least three objects" consistently, and 43.3% not using "phrases with a noun and verb" consistently at exit. More than half of the children who entered the programme with minimal speech exited the programme with a similar language profile. A small percentage of children (1.2%-4.7%) regressed in their language level over time. Conclusions: Despite advances in early intervention, and access to services at a younger age, around a quarter of individuals with ASD in this study exited early intervention with significant communication needs. Our findings are considered in relation to the literature and clinical implications, and future research directions are discussed.