Relatively little attention has been paid to the understanding of process innovation, compared to the well-researched product innovation. This paper contributes to improve our understanding of process innovation and its specific process capabilities and performance by exploring, across many industries, 4,608 process-oriented innovators. Process innovation is defined as adoption of technologically new or significantly improved production methods, including changes in equipment, organisation or methods of product delivery. Process-oriented innovators or process seekers are those firms which usually only introduce process innovation, and no product innovation. These have received less attention by scholars. Results show that process innovation without also organisational innovation complements constrains innovative performance. Complex process-based innovation complementarities result from the simultaneous development and integration of new machinery and organisational innovations.