Reports on 4 studies addressing the structure of environmental attitudes. Based on P. C. Stern and T. Dietz' (1994) value basis theory for environmental attitudes, it was predicted that concerns for environmental issues would form 3 correlated factors based on the relative importance a person places on self, on other people, and on plants or animals (egoistic, altruistic, and biospheric environmental concerns, respectively). Study 1 presents the results from a confirmatory factor analysis of the proposed 3-factor model among a sample of 1,010 US undergraduates. Study 2 presents the results from a telephone survey of 1,005 US respondents (aged 18-89 yrs). Study 3 examined the relationship between the 3 identified types of environmental concerns, existing measures of environmental attitudes, empathy, and social value orientation among 148 US undergraduates. Study 4 presents the results from a multi-group confirmatory factor analysis examining the factor structure of environmental concerns among college students in 10 countries in Latin America. Additional analyses are provided on the relationship between values and environmental concerns. Taken together, the results provide evidence for the distinction between egoistic, altruistic, and biospheric environmental concerns.