The number of young adult chronic patients, particularly males, has risen not only in community mental health programs but also among the inpatient populations of state hospitals. To assess the chronicity of these young adult patients, the authors divided the state hospital inpatient census into three groups based on length of stay. They found a considerable increase in the proportion of male admissions age 21 to 44 who remained hospitalized for three months or more. The three groups also differed in patient characteristics and prognosis for release. The authors conclude that the increasing number and proportion of younger patients, with their markedly different service needs, will almost inevitably alter the nature of the state hospital program for decades to come.