We evaluated a new guideline, in the form of a "checklist of considerations," to support end-of-life decision making in the treatment of demented patients with pneumonia. Questionnaires were sent to nursing home physicians (NHPs) in The Netherlands at three times: before implementation of the checklist (concerning 91 individual patients), during use of the checklist (concerning another 107 individual patients), and after data collection (concerning the targeted patient category of demented nursing home patients with pneumonia as a whole). In the last questionnaire, one NHP from each nursing home (n = 55 NHPs) gave his or her general opinion about the checklist. We measured the usefulness of the checklist in supporting decision making and its frequency of actual use. The NHPs accepted the contents of the checklist for use in the targeted patient category. It was used in 46% of the incident cases of pneumonia. The checklist was considered more useful in supporting decision making for the targeted patient category (85% of the NHPs) than for the individual patient (47%). Possible explanations for this discrepancy in "usefulness" include the difference in the nature of the outcome measures and the fact that the checklist was used more frequently for the "easier cases." Information on individual patient level, patient category level, and nursing home and NHP characteristics is used to suggest checklist improvements.