Dr. Erwin L. LeClerg, 80, a retired scientist, administrator and statistician with the U.S. Department of Agriculture, died of cancer Monday at Montgomery General Hospital in Olney.

Dr. LeClerg was a native of St. Louis and grew up in Denver. After graduation from Colorado State University in 1924 with a degree in botany, he began working as a plant pathologist for the USDA at Iowa State University in Ames, Iowa. At the same time, he earned a master's degree from the university.

He returned to Colorado to work as a plant pathologist at Colorado Agricultural College in 1925 and remained there for the next five years. He rejoined the USDA in 1930 and conducted research on sugar beet diseases at the University of Minnesota, where he subsequently received a doctorate in plant pathology.

In 1940, he was transferred to Baton Rouge, La., where he directed the USDA's Southern States Potato Improvement Program.

Dr. LeClerg moved to the Washington area in 1946 and served for two years as budget examiner in the old Bureau of the Budget. In 1948, he returned to Agriculture and worked until 1954 as a research coordinator.

He was named director of the Biometrical Services Division of the Agricultural Research Service in 1954 and remained in that position until he retired in 1964.

While living in Washington, Dr. LeClerg taught a course in experimental statistics at the University of Maryland. After his retirement, he was a visiting professor in the department of statistics at the University of Iowa and was chairman of the department of biological sciences at the Department of Agriculture Graduate School in Washington. Dr. LeClerg was a coauthor of a textbook on applied statistics and the author or coauthor of more than 60 technical articles.

In 1960, Colorado State University presented Dr. LeClerg an award for "outstanding scholastic and professional achievement." The USDA's Organization of Professional Employees awarded him with its man of the year award in 1963.

Since 1972, Dr. LeClerg and his wife of 55 years, Phylis, had lived at Roosmoor Leisure World in Silver Spring, where he served as president and vice president of the community council.

Dr. LeClerg was a fellow of the American Statistical Association, the Royal Statistical Society of London, the Washington Academy of Sciences and the American Association for the Advancement of Sciences as well as other professional groups.

In addition to his wife, survivors include a son, Robert Erwin, of Weaverville, N.C.; a sister, Benita Awes of San Diego, and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Sigma Chi Foundation, or to the Interfaith Chapel at Rossmoor Leisure World in Silver Spring.