A foam cushion was designed for wheelchair users who propel their wheelchairs with the assistance of one lower extremity. It allows users to extend one hip to reach the ground without having to slide forward on the seat, thus maintaining a more erect posture. The cushion was evaluated to identify contraindications for its use. Eleven subjects (10 stroke patients and 1 patient with an above-the-knee amputation) were tested on the Hemi Wheelchair Cushion and on a second cushion chosen by their primary occupational therapists. Seat interface pressures, both before and after dynamic movement, sitting balance, and wheelchair mobility were measured for each cushion. An analysis of mean pressure values revealed no significant difference between the cushion (p = .80). Average pressures after dynamic movement showed a statistically significant difference from pressures before activity (p < .05). Subjective evaluation revealed that the Hemi Wheelchair Cushion did not adversely affect sitting balance or wheelchair mobility, and no contraindications for its use were identified. The results of this clinical evaluation indicate that the Hemi Wheelchair Cushion is an economical and appropriate option for wheelchair users who propel themselves with the assistance of one leg.