Robot-assisted ambulatory training has become an increasingly popular method of rehabilitation. The present study aimed to evaluate the effectiveness of robot-assisted training on walking by measuring changes in gait pattern. In this pilot study, a lightweight, modular, wearable lower-limb robot that supports walking was tested in two male patients who became hemiplegic because of stroke. Wearing the lower-limb robot, 12 weeks of ambulatory training was conducted, 3 days a week, for 45 minutes per session. Gait analysis was conducted using a 3D motion analyzer to measure and evaluate the changes in walking aspects 4 times (pre-training, 6 weeks, 12 weeks, and 24 weeks); the evaluation measured temporal-spatial, kinematic, and kinetic variables. Several variables improved in the hemiplegic patients after the end of 12 weeks of training but regressed somewhat after an additional 12 weeks without ambulatory training. Future studies should be focused on improving certain aspects of the robotic training mechanism, such as the ankle joint torque generator, and should be expanded to include a larger population of controlled study participants.