Volatilization can reduce soil selenium. A method was developed to measure volatile Se from soils and plants using a chamber in which temperature and light conditions were similar to the ambient. Inserting the chamber into the soil isolated a soil column and collected volatile Se for a known period of time. In a laboratory test with a known quantity of dimethyl selenide solution, the Se recovery was 98%. In soil systems with and without plants, the collection of volatile Se was reproducible. The soil and air temperatures inside and outside the chamber were similar because of the chamber design.