In 1995, a radon survey station was set up in the Friuli area (north-eastern Italy). Radon concentration is monitored with a sampling interval of 3 hours. In this work the data recorded from 1996 to 1999 are analysed in a search for a possible correlation between radon anomalies and local earthquakes. The minimum earthquake magnitude required to obtain a radon anomaly at a given distance from the radon recording device is determined. In this way, the selected earthquakes, especially if large, can have their epicentres up to many kilometres away from the radon site. Every datum exceeding the 2-sigma threshold has been considered as an anomalous value. Significant variations in radon concentration have been observed in relation to local events. The most interesting seismic events are characterized by epicentres that are less than 40 km from the radon station and with a magnitude greater than 3.0, followed by seismic series.