This study assesses the nutritional status of Maasai pastoralists living in a period of great social, economic and ecological changes in Kajiado County, southern Kenya. Data on weight, height, skinfolds, and circumferences were collected from 534 individuals in the year 2000. The data were used to describe mean differences in human nutrition between ages, sexes, and within and among three Group Ranches. Nutritional data and diet recall data were compared with past studies of Maasai nutrition from 1930 to 2000. Results indicate that nutritional status is poor and has remained so despite numerous changes to the social-ecological system including livelihood diversification, sedentarization, human population growth and decreased access to vegetation heterogeneity. Imbirikani Group Ranch had better access to infrastructure and markets and some measures of nutritional status were better than for individuals in other group ranches. However, nutritional status remains poor despite transitioning to greater market integration.