The use of a computer-controlled multirobot system with sensors in batch manufacturing and assembly tasks offers a number of significant advantages. These include cost savings, reliability, tolerance of working environments unacceptable to humans, and an adaptability to both structured and unstructured environments through simple reprogramming. The end results are improved productivity, efficiency, and flexibility in manufacturing and automation. However, the use of two or more cooperating robots has not been fully exploited to date. Current industrial practice employs simple time-space coordination which does not allow more than one robot working in a common workspace, such coordination and control results in under-utilization of robots. With the increasing demand for high performance manipulators and efficient multirobot manufacturing cells, there is a vital need to develop theoretical and design methodologies that will solve the generic problems faced by industrial robots working cooperatively. If multirobot systems are to be used in manufacturing and assembly tasks, a thorough knowledge of the dynamics of such systems is essential. This paper formulates the dynamics of two robots cooperating to move a rigid body object. The analysis is based on Newtonian mechanics with screw calculus and dual transformation matrices.