1x1 - Death Runs Wild

September 17, 1960

Story tells of a demented woman out to kill private eye Anthony George. The instrument of death, as it turned out, was, a wild stallion she stocked on her ranch. Her motive was revenge. On a previous case, the private eye had brought her lover to justice and the gas chamber.

1x2 - Interrupted Honeymoon

September 24, 1960

1x3 - The Cyanide Touch

October 1, 1960

1x4 - Lady on the Brink

October 15, 1960

Checkmate comes to the aid of a woman with a traumatic past when it becomes evident that someone is trying to make it appear she's mentally unstable. discrediting her eye-witness testimony at a murder trial.

1x5 - Face in the Window

October 22, 1960

1x6 - Runaway

October 29, 1960

1x7 - Target: Tycoon

November 5, 1960

1x8 - The Deadly Shadow

November 12, 1960

1x10 - Moment of Truth

November 26, 1960

1x11 - The Mask of Vengeance

December 3, 1960

1x12 - The Murder Game

December 17, 1960

Attorney Emory Olivant invites Corey, Sills and Dr. Hyatt to a party. Once all the guests have arrived, Olivant announces that they are going to play a game—a murder game in which he will be the killer.

1x13 - The Princess in the Tower

December 31, 1960

1x14 - The Terror from the East

January 7, 1961

1x15 - The Human Touch

January 14, 1961

Arguably the finest episode of the series, featuring guest star Peter Lorre as an ex-con criminal mastermind determined to wreak revenge on master criminologist Sebastian Cabot. An intricate series of cat and mouse moves between the two geniuses culminates in a surprise and ultimately poignant ending, befitting the episode title. This episode stresses the close friendships between the three detectives of CHECKMATE INCORPORATED as it contrasts with that of the brilliant, but soulless Lorre. Directing, writing and acting are all exemplary.

1x16 - Hour of Execution

January 21, 1961

1x17 - Don't Believe a Word She Says

January 28, 1961

1x18 - Laugh Till I Die

February 4, 1961

1x19 - Between Two Guns

February 11, 1961

1x20 - A Matter of Conscience

February 18, 1961

1x21 - Melody for Murder

February 25, 1961

1x22 - Phantom Lover

March 4, 1961

1x23 - The Gift

March 11, 1961

1x24 - One for the Book

March 18, 1961

1x25 - The Paper Killer

March 25, 1961

1x26 - Jungle Castle

April 1, 1961

1x27 - The Deadly Silence

April 8, 1961

1x28 - Goodbye Griff

April 15, 1961

""Ex-convict Griff Nolan is jealous because his wife Libby earns more as a magazine editor than he does as a mechanic. More domestic strife develops when Griff becomes jealous of Libby's boss Lewis Bates --- and buys a gun."" -- TV Guide

1x30 - Voyage Into Fear

May 6, 1961

1x31 - Tight As a Drum

May 13, 1961

1x32 - Death by Design

May 20, 1961

1x33 - The Thrill Seeker

May 27, 1961

1x34 - Hot Wind in a Cold Town

June 10, 1961

1x35 - A Slight Touch of Venom

June 17, 1961

1x36 - State of Shock

June 24, 1961