The CAMEX-4 AMPR Brightness Temperature (TB) dataset was collected by the Advanced Microwave Precipitation Radiometer (AMPR), which was deployed during the Fourth Convection and Moisture Experiment (CAMEX-4). AMPR data were collected at four microwave frequencies (10.7, 19.35, 37.1 and 85.5 GHz) for the period of 26 August 2001 through 24 September 2001. The purpose of the CAMEX-4 mission was to study hurricanes over land and ocean in the U.S., Gulf of America, Caribbean, and Western Atlantic Ocean in coordination with multiple aircraft and research-quality radar, lightning, and radiosonde sites.