This research study focused on the use of cooperative groups to facilitate class-wide participation, especially for initially low participants. Undergraduates from three sections of a relatively large educational psychology course recorded their class participation in all course units. Four of the five units in each section offered either individual credit or group-plus-individual credit for participation. At the end of the first unit, instructors assigned students to five-or six-member cooperative groups based on their participation levels during the first unit. At the end of each remaining unit, instructors asked one student to randomly select 2 of 4 discussion days from that unit for individual participation credit. Additionally, in 2 of the 4 credit units, the instructor also made group bonus credit available if every present member of a group participated at least once on each selected credit day. The individual-plus-group credit contingency produced greater class-wide participation than individual credit alone for the total sample across the combined sections and for initially low participants in two of the three sections.