While several investigators have reported relationships between ethnic background and expression of pain, such relationships are in fact highly problematical. Few studies of pain and ethnicity have used quantitative measures of pain combined with multivariate methods of data analysis. Most have focussed on populations which, unlike many in the United States today, are characterized by highly distinct ethnic groups. The study reported here interviewed 536 persons recently treated for forms of cancer known to cause significant pain. Pain was assessed using standard, well validated instruments, including Graphic Rating Scales anchored in several alternative time-frames and the McGill Pain Questionnaire. The study took place in an area with a low proportion of recent immigrants and only small concentrations of distinct ethnic minorities. No statistically significant relationships were observed between ethnic identity and measures of pain sensation. However, pain described in affective terms according to the McGill Pain Questionnaire did vary among ethnicities. This observation suggests that cultures associated with specific ethnic identities still condition individual expression of pain despite the high degree of assimilation that has occurred among ethnic groups in the United States.