In Mauritius, Kreol is the home language of the majority of school children, while English is the main language of literacy and the main written medium of instruction as from the first year of primary schooling. This has had a backwash effect on the preschool sector, where English is introduced. A cross-sectional study of local preschools revealed that while English number names are systematically taught, there is less planning in the teaching of general English vocabulary. This article reports on a comparative study of a "regular" English preschool class and an Oral English Intervention Programme in two local preschools over 2005. The comparison between pre-test and post-test results showed that the children in both programmes improved significantly in receptive English vocabulary, with the experimental subjects unsurprisingly outperforming the 'regular' group. However, the implementation of the intervention programme revealed the many potential challenges of teaching English to pre-schoolers in an English-poor environment.