Over the past ten years, dramatic changes have been seen in the numbers of mildly mentally retarded students in the United States; in particular, a 30 percent decrease in the number of mildly mentally retarded students between 1976 and 1986 has been well documented. These changes have occurred in response to litigation in the federal courts, concerns about the fundamental nature of mental retardation (particularly whether persons from "adverse" socioeconomic circumstances can be classified as mildly mentally retarded), and disputes about the nature and meaning of adaptive behavior. Two issues are critical in the changing status and diagnosis and treatment of the mildly mentally retarded. The first is the fundamental meaning of the diagnostic construct of mild mental retardation, and the second is the outcome of special education programs for students classified as mildly mentally retarded. This issue of outcomes may be addressed more effectively in current special education reforms, through use of evidence from follow-up studies to design curricula, and in basic research on cognitive modifiability. These trends may lead to the development of more effective programs in the future which make genuine differences in the capabilities of persons who used to be, and in some cases still are, classified as mildly mentally retarded. A list of 40 references is appended. (CB)