Using data from a survey of 769 firms, this paper provides empirical evidence of the nature of innovation and its determinants within knowledge intensive business services (KIBS). The aim of the paper is to analyse how KIBS innovate and whether they innovate differently in three Canadian knowledge intensive business industries: Computer System Designs and Related Services; Management, Scientific and Technical Consulting Services; and, Architectural, Engineering and Related Services. There are clear differences in the innovation profiles of the three sectors, which suggest that KIBS cannot be analysed as an undifferentiated group of establishments. However, there are also important within-sector differences that call for further investigation.KIBS, Computer System Designs and Related Services, Management, Scientific and Technical Consulting Services, Architectural, Engineering and Related Services, innovation, system of innovation, Quebec,