Changes in patterns of maladaptive behavior related to age-associated adaptive declines were investigated in 529 adults with mental retardation. Although individuals with no significant adaptive decline displayed stable patterns of maladaptive behavior over a 3-year period, those with declines in function showed more variable patterns. Certain maladaptive behaviors were related to the onset of adaptive declines, with some becoming of increasing concern even before adaptive declines were noted (e.g., lack of boundaries). Other behaviors increased as adaptive declines developed (e.g., withdrawal). In general, findings suggest similarities in the course of age-associated dementia of adults with and without mental retardation and indicate that increases in selected areas of maladaptive behavior may be early indicators of concern for individuals at risk.