Northwestern Buenos Aires province is located within the Pampas region of Argentina. Agricultural practices have extensively modified native grasslands in a relatively short period, leaving no intact pristine areas. Based on data collected between 2006 and 2015 at 153 ponds in agricultural landscapes, we compiled an annotated list of the amphibians of northwestern Buenos Aires province. We report 13 extant species of amphibians, which represent 43% of the known amphibian diversity in Buenos Aires province, and extend the ranges of three species. Three species found only in herpetological collections extend the list to 16 species. Our study is the first long-term survey of amphibians conducted in this part of Argentina and provides valuable information for future conservation actions across agricultural landscapes.