This paper examines co-operative innovation and Research and Development (R&D) behaviour between Argentine and Spanish firms. Based on theoretical perspectives from the literature, we present empirical evidence obtained from 104 firms of patterns of cooperation in several processes and out-puts, highlighting firm characteristics, the motives of the collaborating parties, types of partners, R&D and innovation activities, leadership, and obstacles to cooperation. Our results reveal that the determinants of success differ considerably among countries depending on the sector, the firm specific characteristics and funding.These differences have important implications for public policy and instruments to support R&D and innovation activities.