Research examining the costs of disability transitions of individuals 65 years of age and older has been published with the reference provided below. A manuscript describing research of Medicare beneficiaries under the age of 65 who received disability benefits remains in development. As noted in the last report, this research examines characteristics of Medicare beneficiaries under age 65 who receive benefits for reasons other than end stage renal disease. Descriptive statistics reveal at the time of the first interview, the five most cited primary reasons for Medicare eligibility were mental disorder (21%), mental retardation (13%), back/spine/disc problems (9%), rheumatoid or other type of arthritis (7.3%), and stroke (3.8%). Having at least three comorbidity conditions was reported by 49% of the sample at baseline. Statistical analyses revealed the percentage of individuals with no mobility limitations on both interviews decreased with age while the percentage for stable mobility limitation increased. The groups reporting improving and worsening of mobility limitations were comparable in magnitude, but both presented a small increase after age 40. As number of comorbidities increased, the percentage of individuals with no ADL difficulties on both interviews decreased. In addition, the percentages of people reporting no limitations on both interview years were higher for ADL than mobility. Relative to health conditions, Medicare beneficiaries with mental disorders tended to report large percentages of stable or no mobility limitation, while they report very little movement improving or worsening. Similar patterns were noted for individuals with mental retardation. Individuals with back/spine/disc problems and any type of arthritis demonstrate similarities relative to mobility, ADL and IADL measures of functional disability. For mobility, they report a very large percentage in the stable limitation group, with little movement (improving or worsening). For ADL, the largest percentages are still stable for functional disability, but more people reported no disability, improving, and worsening transitions. A similar pattern is seen for IADL, though more people reported to have IADL functional disability. In the stroke group, stability was reported most often for mobility limitation, with little movement (improving or worsening). For ADL, most individuals reported no or stable functional disability, with a substantial movement. IADL had a similar pattern, but fewer people reporting no functional disability and more reporting stable functional disability. Demographic characteristics such as an increased number of comorbidities and underweight individuals were associated with worsening mobility limitation. Examination by health condition revealed large percentages of stability in mobility across the samples with the back/spine/disc and arthritic conditions group reporting more movement in ADLs and IADLS compared to other health conditions.