Cudrefin (kydʁəfɛ̃) is a municipality in the district of Broye-Vully in the canton of Vaud in Switzerland.
Cudrefin is first mentioned in 999 as Curtefin.
Cudrefin has an area, , of . Of this area, or 60.7% is used for agricultural purposes, while or 22.8% is forested. Of the rest of the land, or 8.0% is settled (buildings or roads), or 0.5% is either rivers or lakes and or 8.2% is unproductive land.
Of the built up area, housing and buildings made up 3.8% and transportation infrastructure made up 2.7%. while parks, green belts and sports fields made up 1.5%. Out of the forested land, all of the forested land area is covered with heavy forests. Of the agricultural land, 52.8% is used for growing crops and 6.0% is pastures, while 1.9% is used for orchards or vine crops. All the water in the municipality is flowing water.
The municipality was part of the Avenches District until it was dissolved on 31 August 2006, and Cudrefin became part of the new district of Broye-Vully.
On 1 January 2002 the former municipality of Champmartin merged into the municipality of Cudrefin, keeping the name Cudrefin.
The municipality is located along Lake Neuchâtel. It consists of the village of Cudrefin, the hamlet of Montet and since 2002, the village of Champmartin.
The blazon of the municipal coat of arms is Per fess chief per pale Gules and Argent overall a Trout nainaint Azure and Or a Crayfish Gules. The new coat of arms includes the symbols of both Cudrefin (trout) and the former municipality of Champmartin (crayfish).
Cudrefin has a population () of . , 10.6% of the population are resident foreign nationals. Over the last 10 years (1999–2009 ) the population has changed at a rate of 42.6%. It has changed at a rate of 36.6% due to migration and at a rate of 6.8% due to births and deaths.
Most of the population () speaks French (638 or 75.6%), with German being second most common (170 or 20.1%) and Portuguese being third (14 or 1.7%). There are 9 people who speak Italian and 1 person who speaks Romansh.