This study assessed whether two persons with multiple disabilities would be able to control environmental stimulation using limb swing with a gyration air mouse and a newly developed limb movement detection program (LMDP, i.e., a new software program that turns a gyration air mouse into a precise limb movement detector). The study was performed according to an ABAB design, A representing baseline and B representing intervention phases. Data showed that during the intervention phases both participants significantly increased their target response to produce environmental stimulation by activating the control system through limb swing. Practical and developmental implications of the findings are discussed. (Contains 4 figures.)