Objectives: To examine the extent of agreement between nursing home residents' (or their proxies') reports of pain presence and intensity as derived from an interview questionnaire and the Minimum Data Set (MDS) nearest to the interview date. Design: Cross-sectional comparison of the 2 data sources on pain measurements. Setting: Nursing homes included in evaluation projects of EverCare program and Minnesota Senior Health Options. Participants: Nursing home residents (n = 3100) were grouped based on the type of respondent answering the interview questionnaire: resident, family proxy, or staff proxy. Measurements: We used kappa statistics and multinomial logit regression to examine agreement between the interview questionnaire and the MDS on pain presence and intensity. Results: Presence of pain was reported 1.3 to 1.8 times more often on the questionnaire, depending on the respondent group. Agreement on the presence of pain was slight to fair (kappa = 0.17 to 0.28) between the MDS and the questionnaire. There was slight agreement on pain intensity (kappa = 0.13 to 0.18). The family proxy respondent group showed the largest discrepancy between questionnaire and the MDS in reporting of pain presence and intensity. The staff proxy respondent group had better agreement on pain intensity than did the other respondent groups, but it achieved only slight agreement (kappa = 0.18). Conclusions: Detecting and quantifying pain in nursing home residents is complex. Pain information is best obtained directly from residents; observations should be standardized. The MDS should be revised accordingly.