The first national study of 3,898 publicly funded prekindergarten classrooms (81-percent response rate) currently operating in 40 States found that 10.4 percent of prekindergarten teachers reported expelling at least 1 preschooler in the past year; 19.9 percent of these preschoolers were expelled more than once. Nationally, 6.67 preschoolers were expelled per 1,000 students enrolled; this rate is 3.2 times the rate of expulsion for K-12 students. Expulsion rates were highest for older and African-American preschoolers. Boys were four times more likely than girls to be expelled. Expulsion rates were lowest for classes in public schools and Head Start and highest in faith-affiliated centers and for-profit child care. In addition to expulsion, placement into alternative settings for expelled adolescents has increased markedly in States, but only recently has there been evidence that this trend includes young children. Possible factors that contribute to this trend are the increase in the number of children participating in preschool programs; preschool children with disabilities; changes in family demographics; the quality of preschool services and personnel; the performance culture and readiness for preschool; definitions of behaviors that qualify for expulsion; Federal legislation that promotes child discipline; State laws that encourage preschool policies that undermine developmental practices; and the role of the physician. Further research is needed in order to identify and analyze the factors that may contribute to increased expulsions, including the extent to which the current national climate of school security and violence prevention in K-12 is influencing discipline policy in early childhood programs. Other recommendations are also provided. 1 figure and 87 references