This was the first (and only) time that Joseph Cotten and Katharine Hepburn appeared together since they starred in the original Broadway production of "The Philadelphia Story" in 1939.
The play "A Delicate Balance" won the Pulitzer Prize in Drama in 1967.
Kim Stanley suffered a nervous breakdown shortly after filming began and was replaced by Kate Reid. Stanley wouldn't make another film until Frances (1982).
Adapted from a play by Edward Albee. The original Broadway production, starring Jessica Tandy and Hume Cronyn, opened at the Martin Beck Theatre in New York on Sept. 12, 1966, ran for 132 performances and was nominated for the 1967 Tony Award for the Best Play. It was produced in London early in 1969, under the direction of Peter Hall. The leads were played by Peggy Ashcroft and Michael Hordern.
Kate Reid replaced Kim Stanley during rehearsals due to Stanley's erratic behavior. Reid would also play roles for which Stanley was original choice in Questa ragazza è di tutti (1966) and Atlantic City, U.S.A. (1980).