For the majority of migrants, family is the last redoubt of mother tongue maintenance. Understandably, there has thus been a large body of literature on the importance of parental influence on the language behaviour of their children. While many of the studies focus on either reversing language shift (Fishman 1991) or bilingual education (Barron-Hauwaert 2004), much less attention has been given to the immediate effect of parental language choice on that of their children in everyday interaction. In the present study, eight Chinese migrant children, aged 5 to 11 years, were monitored for one calendar year using Conversational Round (CR) as the primary unit of analysis. Results show that parental use of English sharply increased the use of English by the children and, if parents responded in English to code-switching by the children, there was only a slight chance of the children switching back to Chinese in the subsequent turn. It is therefore indicated that language choice is a substantially effective parental strategy for the maintenance of the mother tongue in children of this age group.