This Letter proposes a novel simultaneous repetitive motion planning (SRMP) scheme of two redundant robot arms for cooperative manipulation. To remedy the joint-angle drift phenomenon, two SRMP subschemes are exploited at the joint-acceleration level. The subschemes are then simultaneously reformulated as two quadratic programs (QPs), which are finally unified into a QP problem solving. Theoretical analysis and computer simulation based on two three-link robot arms both substantiate the feasibility and effectiveness of the proposed SRMP scheme. • A two-manipulator robotic system is investigated. • A novel simultaneous repetitive motion planning scheme is proposed. • Theoretical analysis of GD-ZD type is presented. • A unified quadratic program is achieved. • Computer simulation substantiates the effectiveness of the proposed scheme.