[en] The LPNHE is a joint research unit (UMR 7585) of the National Institute of Nuclear Physics and Particle Physics (IN2P3), Institute of the National Centre for Scientific Research (CNRS), UPMC and Paris Diderot Paris 7. It hosts several research teams and technical services (computers, electronics, mechanical), and two support services (administration, logistics). The laboratory is engaged in several major experimental programs pursued in the framework of international collaborations with very large research facilities around the world, centers of particle accelerators and observatories. The research programs cover current issues in particle physics, astro-particle and cosmology. This report presents the activities of the laboratory during the years 1998-1999: 1 - Forewords; 2 - Physics experiments: LHC Physics with ATLAS, search for new physics at LEP, DIRAC experiment, Neutrinos oscillation with NOMAD, TONIC and HERA-H1 experiments, CP Violation (BaBar), DΦ experiment at Tevatron, high-energy gamma astronomy, Supernovae, Pierre Auger Laboratory); 3 - Technical activities and means (electronics, computers, mechanics departments); 4 - Laboratory life (Teaching, Administration and general services, Internal and external activities); 5 - Dissemination of scientific information; 6 - List of publications; 7 - staff