This study provides the first comprehensive estimates of children and youth working under conditions that violate federal and state child labor laws. Using a variety of sources with employment-related data on children and youths, some of the main findings are that:

An estimated 148,000 minors are employed illegally in an average week - working too many hours or in hazardous occupations - and 290,000 are employed illegally at some point during a year.

Of youth who are employed, one-tenth (10.6%) of 15-year-olds are working in violation of child labor laws, compared to 1.6% of 16- and 17-year-olds, who have fewer legal restrictions.

The total number of hours worked illegally is about 113 million per year, for which these minors are paid over $560 million;

Males, whites, and youths living in the Midwest, West, and non-metropolitan areas are the most likely to be working in violation of child labor laws;

Youths working illegally in hazardous jobs earn on average $1.38 per hour less than legal young adults in the same occupations, which combined with the savings from employing youths for excessive hours rather than young adults adds up to a total employer cost savings from illegal child labor of roughly $155 million per year.

The large number of minors found to be working illegally in an average week raises important policy concerns about the health and well-being of these youths. This study also adds weight to the recent recommendations of the NIOSH Child Labor Working Team concerning the development of high-quality employment data on children and youths, to improve estimates of illegal employment and study of its effects.