We examined the effectiveness of a 6-month home-based program designed to increase physical activity and improve fitness in three generations of women (n=35), organized as triads (n=9) or quads (n=2). Maternal grandmothers (M=62 y), mothers (M=37 y), and daughters (M=10 y) were instructed to perform aerobic, muscular strength, and flexibility activities at least 3 days per week. Physical activity was measured pre- and post-intervention using Activitygram and pedometer step counts (3-day average). Health-related fitness was assessed using Fitnessgram. Subjects completed 73 % of the recommended exercise bouts and one triad dropped out of the study due to time constraints. Daughters significantly increased their participation in flexibility activities (.83 + 1.60 to 4.0 + 2.10 d/wk, P=.029), but participation in aerobic (3.33 + 2.16 to 4.33 + 1.21 d/wk, P=.45) and muscular strength activities (2.33 + 2.73 to 3.67 + 2.50 d/wk) did not increase. Mothers and grandmothers significantly increased their participation in flexibility (.43 + .79 to 3.42 + 2.14 d/wk, P=.004; 1.57 + 1.90 to 4.14 + 1.86 d/wk, P=.001, respectively), aerobic (1.43 + 1.90 to 3.86 + 1.46 d/wk, P=.018; 1.71 + 1.11 to 4.85 + 1.35 d/wk, P=.001, respectively), and muscular strength activities (.57 + .98 to 3.42 + 1.72 d/wk, P=.001; .71 + 1.25 to 3.57 + 2.30 d/wk, P=.012 ). All 3 groups increased their step counts by 30%, although the only statistically significant improvement occurred with the mothers (mothers=8141 + 1877 to 10648 + 2493, P=.02; daughters=10,765 + 5834 to 13,980 + 2589 , P=.25; grandmothers=8,711 + 3836 to 11,340 + 3507, P=.14, respectively). Fitness changes corresponded with physical activity participation. Daughters increased their push-up (21.46 + 9.11 to 33.36 + 13.28, P=.002) and sit-up (25.27 + 7.43 to 34.64 + 9.43, P=.002) scores. Systolic blood pressure (106.67 + 6.00 to 101.56 + 6.21, P=.05), and body fat (25.21 + 6.00, P=.03) also decreased. Mothers increased their push-up (22.0 + 10.28 to 30.80 + 9.30, P=.002), sit-up (24.80 + 13.60 to 43.60 + 15.73, P=.002), and flexibility scores (26.55 + 12.59 to 30.15 + 12.49 in, P=.008). Grandmothers increased their sit-up scores (17.67 + 10.93 to 26.50 + 9.48, P=.04) and decreased their percent body fat (41.38 + 3.77 to 38.67 + 4.58, P=.004). Home-based physical activity interventions may increase physical activity and improve health-related fitness in three generations of women.