Leonard S. Frank, president of a family-owned corrugated box manufacturing company, died Monday at Sinai Hospital of respiratory illness. He was 70 and lived on Copperfield Road in Pikesville.

Services for Mr. Frank were held yesterday at the Levinson funeral establishment.

He was president of Sig. G. Frank and Bros., which had been started by his father in 1915. He had joined the company after doing an apprenticeship at a box company in New York City.

Born in Baltimore, he was a 1939 graduate of Forest Park High School, where in addition to his school work, he played football. He had a lifelong interest in sports and was a founder of the Summit Country Club.

He served in the Navy during World War II as a sonarman on amphibian planes based in the Azores.

Mr. Frank is survived by his wife, the former Annette Scherr; two daughters, Nancy Carp and Ellen Frank, both of Pikesville; two brothers, Dr. Frederick Frank of Woodside, Calif., and Donald Frank of Baltimore; three sisters, Ethel Spiegel and Johanna Safer, both of Coral Gables, Fla., and Adele Cohen of Baltimore; and one grandson.