Medication adherence is a substantial problem in the elderly. It may be even more important among elderly persons with memory problems, since other factors that lead to non-adherence may be compounded with the memory problems themselves. The objective was to determine whether a model that integrates research on medication adherence from several research domains is useful in understanding adherence in elderly patients. The methodology involved a cross-sectional observational study using a convenience sample of 63 patients drawn from a university-affiliated outpatient memory disorders clinic. The primary measure of medication adherence was caregivers' reports of patients' medication adherence. Patients and their caregivers were asked questions assessing their beliefs about the seriousness of each condition for which a medication was prescribed and the likely outcome of that condition without treatment. Additional data collected included presence of side effects, total number of medications taken, and patients' mood and cognitive status. Multilevel path analysis confirmed several model-based predictions. Caregivers' reports of adherence were predicted by estimates of disease outcome, the presence of side effects, and patients' relying on themselves to remember to take medications. Results partially confirm the integrative model in understanding medication adherence in these patients. Patients' beliefs about the likely effect of medication treatment for their condition and the presence of side effects influence reported medication adherence. Results thus suggest that efforts to educate patients about the likely response of their medical condition to treatment and to assess and deal with medication side effects might improve patient adherence.