Despite improvement in prognosis of colorectal cancer, colorectal cancer survivors often suffer from adverse effects of cancer treatment, including reduced health-related fitness level. Therefore, this study aimed to examine the feasibility and efficacy of the 6-week home-based exercise program on the level of physical activity and physical fitness in stage II to III colorectal cancer survivors. Seventy-two stage II to III colorectal cancer survivors were randomly assigned to either a home-based exercise (n = 38) or usual care (n = 34) group for 6 weeks. The goal of the home-based exercise program was to increase the level of exercise to 18 metabolic equivalent task hours per week. The primary and the secondary outcomes of this study were physical activity level and physical fitness, respectively. A total of 57 participants (79.2%) completed the trial. Intention-to-treat analysis indicated that moderate physical activity level increased significantly by 269.4 ± 260.6 minutes per week in the exercise group (mean between-group difference, 254.6 minutes; 95% confidence interval, 172.7-434.7; p < 0.001). Physical fitness measured by using the step test (-3.9 vs. 2.6, p = 0.012) and push-up test (3.0 vs. -1.2, p = 0.012) also improved significantly in the exercise group compared to the control group. The 6-week home-based mixed aerobic and resistance exercise program was feasible and effective for increasing physical activity level and physical fitness in stage II to III colorectal cancer survivors.