- George C. Scott
- Justin Playfair aka Sherlock Holmes
- Joanne Woodward
- Dr. Mildred Watson
- Jack Gilford
- Wilbur Peabody
- Lester Rawlins
- Blevins Playfair
- Al Lewis
- Messenger
- Rue McClanahan
- Daisy Playfair
- Ron Weyand
- Dr. Strauss
- Oliver Clark
- Mr. Small
- Theresa Merritt
- Peggy
- Jenny Egan
- Miss Finch
- Jane Hoffman
- 2nd Telephone Operator
- Michael McGuire
- Telephone Guard
- Eugene Roche
- Policeman
- James Tolkan
- Mr. Brown
- Kitty Winn
- Grace
- Sudie Bond
- Maud
- Staats Cotsworth
- Winthrop
- F. Murray Abraham
- Clyde
- Paul Benedict
- Chestnut Man
- M. Emmet Walsh
- 1st Sanitation Man
- Louis Zorich
- 2nd Sanitation Man
- Ted Beniades
- Taxi Driver
- Worthington Miner
- Mr. Bagg
- Frances Fuller
- Mrs. Bagg
- Ralph Clanton
- Supermarket Manager
- John McCurry
- Lieutenant
- Candice Azzara
- Teenage Girl
- Tony Capodilupo
- Chief
- Matthew Cowles
- Teenage Boy
- Dorothy Greener
- Telephone Operator
- Jacques Sandulescu
- Mr. Brown's Driver
