The Jason-3 mission employs the Advanced Microwave Radiometer (AMR) to provide a tropospheric path delay measurement in support of ocean altimetry. NOAA and EUMETSAT are Jason-3 lead agencies with CNES and NASA/JPL providing implementation support. Jason-3 continues the measurements of TOPEX/Poseidon <xref ref-type="bibr" rid="ref1">1 , <xref ref-type="bibr" rid="ref2">2 , Jason-1, and Ocean Surface Topography Mission (OSTM)/Jason-2 supporting a multidecadal ocean topography studies, including ocean circulation, climate change, hurricane intensity forecasts, and sea level change. The objective of the Jason-3 AMR is to measure the columnar water vapor in the path of the Poseidon radar altimeter (CNES instrument) to correct for water in the atmospheric path delay in the altimeter range measurement. In this paper, the design and performance of AMR are described along with the changes made compared to the predecessor Jason-2 instrument to reduce development risks and improve the stability of the AMR instrument.