The results of this study support the hypothesis that research activity is not a homogeneous activity, and that important differences exist between the determinants of process patenting and product patenting. Further, the effects on concentration and advertising of research depend on the type of research carried on by firms. Concentration and process patenting are positively related and concentration and product patenting are not. There is some weak evidence linking advertising and product patenting. Further, process patenting tends to generate greater industrial concentration.