Background: Dementia patients are at an increased risk for undertreatment of pain, compared with older people without dementia, suggesting a relationship between pain medication prescription and cognitive functioning. Studies on a possible relationship between pain medication and cognitive functioning in dementia patients are ambiguous. Objective: The objective of the study was to investigate whether a relationship between cognition and pain medication is present in patients with dementia with painful conditions. Methods: Initially, 187 people living in Dutch nursing homes participated in the study. Sixty-one patients with dementia and at least one painful condition were included in the final analysis. Logistic regression analyses were conducted to examine the relationship between global cognitive functioning (Mini-Mental State Examination score) and pain medication for the total group and for the largest dementia subgroup, i.e. patients with Alzheimer's disease. Results: No relationships were found between global cognitive functioning and pain medication in the total group and in the group of patients with Alzheimer's disease. Forty-five percent of the participants did not receive any pain medication, despite the presence of a painful condition. Conclusion: Undertreatment of pain in dementia seems to be independent of global cognitive functioning. The use of observational scales, to increase the awareness of other signs of pain, e.g. physical inactivity and behavioural disturbances, is recommended. Even if there is no obvious cause for behavioural disturbances, treatment with relatively mild pain medication should be considered. Adis © 2012 Springer International Publishing AG. All rights reserved.