Photonics on CMOS is a candidate technology for applications where functional integration is needed for improving system performance while reducing size and cost.Functional demonstration of basic building blocks such as a µlaser, a detector, coupling, and link has been realized in previous research projects. As a next step the HELIOS project proposes to integrate photonics components with integrated circuits as a joint effort of major players of the European CMOS Photonics community, in order to enable an integrated design and fabrication chain that can be transferred to EU manufacturers.The objective of the project HELIOS is to combine a photonic layer with a CMOS circuit by different innovative means, using microelectronics fabrication processes.Different types of activities are foreseen:•\tDevelopment of specific, high performance building blocks: WDM sources by III-V/Si heterogeneous integration, fast modulators and detectors, passive circuits and packaging. It also includes the development of dedicated TIA and modulators drivers.•\tBuilding and optimization of the whole "food chain" to fabricate complex functional devices. Several components addressing different industrial needs will be built, including a 40Gb/s modulator, a 10x10 Gb/s transceiver, a Photonic QAM-10Gb/s wireless transmission system and a mixed analog and digital transceiver module for multifunction antennas.•\tInvestigation of more promising but challenging alternative approaches. These concepts offer clear advantages in terms of integration on CMOS for the next generation of CMOS Photonics devices•\tRoadmapping, dissemination and training, to strengthen the European research and industry in this field and to raise awareness of new users about the interest of CMOS Photonics.HELIOS will gather the major European CMOS Photonics and Electronics players and potential users. It will drive the European RTD in CMOS Photonics and pave the way for industrial development