The fourth IASI (Infrared Atmospheric Sounding Interferometer) Conference organized by the Centre National d’Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) will be held in Antibes Juan-les-Pins, France from 11 – 15 April 2016. This Conference aims at sharing and reviewing latest results from the operational and scientific use of nearly 10 years of Hyperspectral observations with IASI instruments on the Metop satellites; in particular from two IASI instruments in orbit since the launch of Metop-B in 2012. IASI has brought increased contributions to operational weather forecasting and has become a well established data source for atmospheric composition and air quality. IASI plays an important role in climate monitoring. IASI data exploitation has further developed significantly in all areas in the last years.