The aim of this study was to estimate the Intensity-Duration-Frequency (IDF) function of extreme rainfall events using rainfall data from rain gauge stations installed in the state of Rondônia, so that this information can later be used to design hydraulic works. We used 41 rainfall stations with historical series of over 10 years, provided by the National Water Agency (ANA). It was found that the equations produced by this study have wide applicability in hydrological works and activities, due to the range of intervals used. In addition, the analyses and statistical tests showed that this expression is viable for use. The historical series used revealed that the average maximum "one-day" rainfall in the state of Rondônia ranged from approximately 71.341 to 173.542 mm/day. Furthermore, it was observed that possible climatic phenomena such as El Niño and La Niña in the region analysed may have generated reductions and increases in the occurrence of extreme rainfall events, respectively.