Problems associated with the use of culture and ethnicity as independent variables in neuropsychological assessment research are reviewed. Culture and ethnicity are complex multidimensional constructs that have defied operational definition. There are no clear criteria for separating cultural and ethnic groups. Cognitive differences between culture and ethnic groups encourage speculations of cultural or ethnic superiority and race-norming. An alternative approach is to focus upon measurable psychological variables that differ between cultural and ethnic groups and potentially impact neuropsychological test scores. To illustrate, research with Hispanic Americans is reviewed to show that English language fluency, length of residence within the United States, years of education, and persistence of poverty all impact test performance.