The paper explores measurement issues surrounding acculturation, discusses the Children's Acculturation Scale (CAS), relates results of several studies dealing with the acculturation and mental health of Mexican Americans, and concludes with a substantiation of the idea that the process of acculturation is stressful and impacts on adjustment. Noting that Mexican Americans are not a homogeneous cultural group and that therefore broad generalizations about Mexican Americans are usually inappropriate, the paper covers such measurement issues as a definition of acculturation, the validation process (including finding and measuring an unacculturated sample), and the measurement of children. The CAS is described as a 10-item Likert-type scale which takes about 5 minutes to complete; on a scale of one to five, individuals scoring near one tend to be very "Mexican" and those scoring near five tend to be very "Anglicized." Studies are cited that involved subjects ranging from grade one children to university level students to randomly selected adults; these studies generally showed that a bicultural orientation produced a healthy psychological adjustment. Other measurement issues include the need to: replicate previous majority/minority culture comparison studies to investigate within-group variability, focus on a broader spectrum of acculturation, and place more emphasis on investigating the process of acculturation and its relationship to mental health adjustment in Mexican American children. (BRR)