Nutritional well-being among older adults is critical for maintaining health, increasing longevity, and decreasing the impact of chronic illness. However, few well-controlled studies have examined nutritional behavior change among low-income older adults. A prospective, controlled, randomized design examined a five session nutrition education module delivered to limited-resource older adults (N = 703) in Congregate Nutrition sites by Cooperative Extension agents. Experimental group participants were significantly more likely than control group participants to increase multivitamin use, to increase calcium supplement use, to read labels of dietary supplements, to carry a supplement and/or medication list, and to discuss such use with their health care professional. The study addresses weaknesses in the literature by using a theoretically derived education component, implementing the intervention within a setting regularly used by low-income older adults, employing randomized assignment to intervention and control conditions, and using hierarchical linear modeling to deal with "nested" data. (Contains 4 tables and 4 notes.)