© 2015 Elsevier Ireland Ltd. Background: Gait abnormalities and vascular disease risk factors are associated with cognitive impairment in aging. Objective: To determine the impact of group-based exercise and dual-task training on gait and vascular health, in active community-dwelling older adults without dementia. Methods: Participants [n = 44, mean (SD) age: 73.5 (7.2) years, 68% female] were randomized to either intervention (exercise + dual-task; EDT) or control (exercise only; EO). Each week, for 26 weeks, both groups accumulated 50 or 75 min of aerobic exercise from group-based classes and 45 min of beginner-level square stepping exercise (SSE). Participants accumulating only 50 min of aerobic exercise were instructed to participate in an additional 25 min each week outside of class. The EDT group also answered cognitively challenging questions while performing SSE (i.e., dual-task training). The effect of the interventions on gait and vascular health was compared between groups using linear mixed effects models. Results: At 26 weeks, the EDT group demonstrated increased dual-task (DT) gait velocity [difference between groups in mean change from baseline (95% CI): 0.29 m/s (0.16-0.43), p < 0.001], DT step length [5.72 cm (2.19-9.24), p = 0.002], and carotid intima-media thickness [0.10 mm (0.003-0.20), p = 0.04], as well as reduced DT stride time variability [8.31 coefficient of variation percentage points (-12.92 to -3.70), p < 0.001], when compared to the EO group. Conclusions: Group-based exercise combined with dual-task training can improve DT gait characteristics in active older adults without dementia.