Co-simulation　of　ADAMS　and　MATLAB　for　designing　and　developing　mechatronics　and　control　system　is　presented　in　this　paper.　The　co-simulation　technology　provides　an　avenue　for　realizing　mechatronics　system　design　loop　and　control　system　design　synchronously　without　the　need　for　building　prototypes.　The　virtual　prototype　developed　in　ADAMS　can　be　used　to　investigate　dynamic　behavior　in　a　3-dimensional　environment.　Though　ADAMS　has　the　capability　of　implementing　a　closed　loop　control　of　the　virtual　prototype,　its　capability　is　quite　restricted.　On　the　other　hand,　MATLAB　is　well　known　for　designing　control　systems.　Co-simulation　allows　us　to　get　the　benefit　of　both.　The　co-simulation　platform　was　used　to　verify　different　features　of　a　unicycle　robot.　Mechanical　drawings　of　the　robot　are　first　created　using　CAD　software,　e.g.,　SOLIDWORKS　and　imported　into　the　ADAMS.　Dynamics　of　the　robot　in　autonomous　mode　are　simulated　using　the　co-simulation　platform　in　which　the　controller　is　designed　and　implemented　using　MATLAB.　Simulation　results　can　then　be　used　to　modify　mechanical　design　and　improve　the　control　method.　Although　the　virtual　platform　is　tested　for　one　specific　system,　it　can　be　easily　used　for　design　of　other　mechatronics　systems　and　control　methods　e.g.,　model　free　control,　learning　control　and　developmental　robotics.　©　Springer-Verlag　Berlin　Heidelberg　2010.