BACKGROUND: Osteoarthritis (OA) of the knee, which is prevalent among older adults in nursing homes, causes significant pain and suffering, including disturbance of nocturnal sleep. One nonpharmacologic treatment option is quadriceps-strengthening exercise, however, the feasibility of such a treatment for reducing pain from OA in severely demented elders has not been studied. This report describes our test of the feasibility of such an exercise program, together with its effects on pain and sleep, in a severely demented nursing home resident. CASE PRESENTATION: The subject was an elderly man with severe cognitive impairment (Mini-Mental Status Exam score 4) and knee OA (Kellgren-Lawrence radiographic grade 4). He was enrolled in a 5-week, 10-session standardized progressive-resistance training program to strengthen the quadriceps, and completed all sessions. Pain was assessed with the Western Ontario and MacMaster OA Index (WOMAC) pain subscale, and sleep was assessed by actigraphy.The patient was able to perform the exercises, with a revision to the protocol. However, the WOMAC OA pain subscale proved inadequate for measuring pain in a patient with low cognitive functioning, and therefore the effects on pain were inconclusive. Although his sleep improved after the intervention, the influence of his medications and the amount of daytime sleep on his nighttime sleep need to be considered. CONCLUSIONS: A quadriceps-strengthening exercise program for treating OA of the knee is feasible in severely demented elders, although a better outcome measure is needed for pain.