A simple data-driven algorithm is used to assess radio frequency interference (RFI) in Global Precipitation Measurement (GPM) Microwave Imager (GMI) data. RFI originates from land-based and space-based sources, affecting the GMI 10 and 18 GHz bands. Land-based RFI demonstrably impacts the GMI 10 GHz data over Europe, China, Japan, and Mexico. Land-based RFI also affects the 18 GHz channels to a lesser degree over particular countries such as Belarus, Libya and Chile. Reflected RFI from the earth surface at 18 GHz from direct broadcast satellites is observed around the continental United States and Hawaii. Geosynchronous direct-broadcast satellites also provide a source of RFI in the GMI cold view. The cold-view RFI is detected and removed in the operational algorithm.