OBJECTIVES: To determine whether dual task-related changes in walking speed were associated with recurrent falls in frail older adults. DESIGN: Twelve-month prospective cohort study. SETTING: Thirteen senior housing facilities. PARTICIPANTS: Two hundred thirteen subjects (mean age 84.4+/-5.5). MEASUREMENTS: Usual and dual-tasking walking speeds (m/s) were calculated on a 10-m straight walkway at baseline. Information on incident falls during the follow-up year was collected monthly, and participants were divided into three groups based on the occurrence of falls (0, 1, and ≥ 2). Recurrent falls were defined as two or more falls during the 12-month follow-up period. RESULTS: Twenty subjects (9.4%) were classified as recurrent fallers. The occurrence of recurrent falls was associated with age (crude odds ratio (OR)=1.11, P=.02), number of drugs (crude OR=1.28, P=.002), and walking speed under both walking conditions (crude OR=0.96, P=.002 for usual walking and crude OR=0.60, P=.005 for walking while counting backward). Multiple Poisson regression showed that only walking speed while dual tasking and number of drugs were associated with incident falls (incident rate ratio (IRR)=0.84, P=.045 and IRR=1.10, P=.004). CONCLUSION: Slower walking speed while counting backward was associated with recurrent falls, suggesting that changes in gait performance while dual tasking might be an inexpensive way of identifying frail older adults prone to falling.