OBJECTIVE To compare the gait of hemiparetic subjects walking on a treadmill with various body weight supports and walking on the floor. METHODS Hemiparetic subjects walked on a treadmill, secured in a harness, with no body weight support and with 15% and 30% body weight relief, and walked on a floor. METHODS Kinematic laboratory of a department of rehabilitation. METHODS Eighteen hemiparetic stroke patients. METHODS Gait cycle parameters and kinesiologic electromyogram of six muscles of the affected side and of two muscles of the nonaffected side. RESULTS On the treadmill, patients walked more slowly because of a reduced cadence, with a longer single stance period of the paretic limb, more symmetrically, and with a larger hip extension (multivariate profile analysis, p<.05). The mean functional activities of the gastrocnemius muscle and of the first crest of the erector spinae of the paretic side were smaller on the treadmill (univariate test, p<.05). Further, the premature activity of the gastrocnemius muscle, indicating spasticity, was less on the treadmill (univariate test, p<.05); correspondingly the qualitative muscle pattern analysis revealed less co-contraction between the gastrocnemius and tibialis anterior muscles in 11 of the 18 subjects. CONCLUSIONS Treadmill training with partial body weight support in hemiparetic subjects allows them to practice a favorable gait characterized by a greater stimulus for balance training because of the prolonged single stance period of the affected limb, a higher symmetry, less plantar flexor spasticity, and a more regular activation pattern of the shank muscles as compared with floor walking.