This paper presents the novel structural analysis of ball-on-sphere system using bond graph technique. The structural analyses carried out are controllability and observability of the system. To achieve these analyses, the system was modelled using bond graph modelling technique. In the modelling procedures, the various subsystems, storage elements, junction structures, transformer elements with appropriate causality assignments and energy exchange that make up the ball-on-sphere system were identified and modelled. The structural controllability and observability properties of the system were carried out on the developed causal bond graph model of the system based on bond graph rules. From the structural analyses, it was established that the developed model was controllable and observable.