The Pre-Elementary Education Longitudinal Study (PEELS), funded by the U.S. Department of Education, is examining the characteristics of children receiving preschool special education, the services they receive, their transitions across educational levels, and their performance over time on assessments of academic and adaptive skills. PEELS includes a nationally representative sample of 3,104 children with disabilities who were 3 through 5 years of age when the study began in 2003-04. The children will be followed through 2009. This report provides selected findings from the first three waves of data collection: school year 2003-04, school year 2004-05, and school year 2005-06. Any reported differences have been tested for statistical significance at the p less than .05 level. These data were collected through several different instruments and activities, including a direct one-on-one assessment of the children, a telephone interview with the children's parents/guardians, and mail questionnaires to the teacher or service provider of each child. Young children with disabilities undergo many transitions during their early school years. These changes include moving from one program to another, from one grade to another, and in some cases, changing both at the same time. Despite these transitions, the number of services children receive is relatively stable as they move from one program to another. Ease of transition varied by child characteristics, such as severity of impairment, academic ability, and social skills. Additionally, parent report of perceived ease of transition also varied by race/ethnicity and family income. Parent and teacher report of ease of transition varied depending on whether the school initiated actions to facilitate the transition process and how much support was provided to teachers. Data on transitions to kindergarten indicate that teachers of children with disabilities used a variety of strategies to facilitate this transition; the number of strategies differed depending on whether the teacher was a regular or special education teacher. Social skills and behaviors of young children identified as having disabilities are a concern of both teachers and parents, and is similar to that found in other studies. Young children who received special education services for three years had more problem behaviors than children who received services for only 1 or 2 years; however, this difference was statistically significant for males only. Both males and females who received services all 3 years had significantly lower social skills than children who stopped receiving special education services between 2003-04 and 2004-05 or between 2004-05 and 2005-06. Eight appendices include: (1) Diagram of Selection of LEA Sample; (2) Weighting Procedures; (3) Nonresponse Bias and Related Analyses; (4) Standard Error Tables; (5) Standard Error Tables for Figures; (6) Number of Children Who Had Test Accommodations; (7) Analysis Variables Used Throughout Report; and (8) Final Augmented LEA Sample Size. (Contains 27 footnotes, 3 figures and 85 tables.)