The aim was to examine the effectiveness of a cycling intervention on body composition in adolescents with Down syndrome (DS). Four participants completed three interventions over eight consecutive weeks. The interventions were: 1) Voluntary Cycling (VC), in which participants cycled at their self-selected pedaling rate 2) Assisted Cycling (AC), in which the participants' voluntary pedaling rates were augmented with a motor to ensure the maintenance of 80 rpms. 3) No cycling (NC), in which the participants acted as controls. Total weight of the participants and percentage body fat of the participants both decreased but not in values that were statistically significant. The only statistically significant value was the ratio of android fat to gynoid fat, which increased. Future research will try to replicate this data with statistically significant values for more cycling adolescents with DS.