The fifth Innocenti Digest looks at what is probably the largest and most ignored group of child workers: child domestic workers. The limited research available on this 'invisible workforce' suggests that 90 per cent are girls, most are 12 to 17 years old, and some work 15-hour days. One of the world's oldest occupations, child domestic work is increasingly becoming a commercialized trade and in many societies child domestics are still considered 'cared for,' and not exploited. A guest commentary by Anti-Slavery International urges that in seeking solutions "nothing can be done to improve the situation of child domestic workers unless employers are involved." The Digest examines challenges for practitioners, reviews national legislation and international standards, describes the work of organizations active in the field, and provides a list of relevant readings.