For young people receiving Supplemental Security Income (SSI), a means-tested cash benefit for children with disabilities, the transition into young adulthood is complicated for several reasons. Health issues, service needs, and lack of access to supports can complicate planning and preparing for future schooling, work, and independent living. These issues are especially pressing at age 18 because, following legislative changes in 1996, child SSI recipients have their benefits redetermined under the adult disability criteria. Some child SSI beneficiaries lose eligibility at this redetermination because they do not meet the adult SSI disability criteria. This paper uses newly released data from the Social Security Administration (SSA), the National Survey of Children and Families (NSCF), to study this transition period for cohorts of child SSI recipients just prior to and after the age 18 redetermination. To date, information on the transition experiences of child SSI recipients has been hampered by data limitations. Our analysis addresses this gap by providing detailed information on an array of program, school, training, rehabilitation, and employment issues facing youth during this transition period.