The oldest-old, those 90 years and older, are the fastest growing segment of the population and the number of dementia cases at these ages will steadily increase over time. It is therefore critical to include this population in clinical research. Evidence to guide recruitment of this group is scarce. We report our experience recruiting the oldest-old to a longitudinal study of aging and dementia. Recruitment activities were grouped into four strategies: direct mailing of recruitment brochures, community outreach, earned media, and referrals. Recruitment sources were recorded based on enrollees’ self-report. Cost was estimated based on personnel time and materials. One hundred forty five new participants were enrolled over 40 months. Community outreach produced the most recruitment (33.8%) followed by earned media (21.4%), direct mail (16.6%) and referrals (15.8%). Earned media and direct mailing were most cost-effective. Local media produced more enrollment and was more cost-effective than national media.