This study examined the loss of proficiency in English as a Second Language (ESL) by Japanese children returning to Japan after a period of time in the United States. Three children who lived in the United States with their families for between 4 and 7 years were interviewed on a monthly basis after their return to Japan. The interviewer engaged the children in various activities in English, and administered English proficiency tests to the children at periodic intervals. The children showed little change in their English abilities during the first 5 to 6 months, but thereafter began to resist speaking English on some occasions, and suffered some loss of fluency, lexicon, and morphology. The specific effects on each child are discussed in detail. (MDM)