FY-3A and FY-3B, launched in May 2008 and Nov 2010, are the first two in a series of seven polar orbiting meteorological satellites due to be launched by China's Meteorological Administration in the period leading up to 2020. The FY-3A/B payload includes four instruments of particular interest for numerical weather prediction (NWP): microwave temperature and humidity sounders, a microwave imager, and an infrared sounder. Data from the FY-3A/B mission were introduced into the ECMWF Integrated Forecasting System and CMA GRAPES model system in order to assess the data quality and the influence of the data on analyses and forecasts. An analysis of first-guess departures has shown the data to be of good quality overall. In observing system experiments, the FY-3 instruments, show considerable skill when added to observation depleted control experiments. These initial results are encouraging and build confidence that the following series of FY-3 instruments will be widely used in NWP data assimilation systems. The work also has witnessed the power of operational NWP systems as tools for diagnose a wide range of instrument and ground segment performance issues and resulted in an improved understanding, in a NWP context, of the characteristics of the FY-3A sounders (IRAS, MWTS and MWHS) and microwave imager (MWRI).