Only works written by Christie (including short stories, the novels and her play Black Coffee) are considered canon by most fans and biographers.

The Poirot books are still under copyright in the United Kingdom. The Mysterious Affair at Styles, The Murder on the Links and Poirot Investigates are now public domain in the US but will not become public domain in the UK until 2046 (70 years after Christie's death). Christie's grandson, Mathew Prichard, now owns the copyright to his grandmother's works.

In 2013, the Christie estate authorised author Sophie Hannah to write a new Poirot book, The Monogram Murders (2014). She later also wrote Closed Casket (2016), The Mystery of Three Quarters (2018), The Killings at Kingfisher Hill (2020) and Hercule Poirot's Silent Night (2023).

Short story collections listed as "ss"
199 The Mysterious Affair at Styles (1920)
299 The Murder on the Links (1923)
399 Poirot Investigates (1924, ss)
499 The Murder of Roger Ackroyd (1926)
599 The Big Four (1927)
699 The Mystery of the Blue Train (1928)
799 Black Coffee (1930 play) (A novelization by Charles Osborne was published in 1998.)
899 Peril at End House (1932)
999 Lord Edgware Dies (1933) also published as Thirteen at Dinner
1099 Murder on the Orient Express (1934) also published as Murder in the Calais Coach
1199 Three Act Tragedy (1935) also published as Murder in Three Acts
1299 Death in the Clouds (1935) also published as Death in the Air
1399 The A.B.C. Murders (1936) also published as The Alphabet Murders
1499 Murder in Mesopotamia (1936)
1599 Cards on the Table (1936)
1699 Murder in the Mews (1937, ss) also published as Dead Man's Mirror
1799 Dumb Witness (1937) also published as Poirot Loses a Client
1899 Death on the Nile (1937) also published as Murder on the Nile and as Hidden Horizon
1999 Appointment with Death (1938)
2099 Hercule Poirot's Christmas (1938) also published as Murder for Christmas and as A Holiday for Murder
2199 Sad Cypress (1940)
2299 One, Two, Buckle My Shoe (1940) also published as An Overdose of Death and as The Patriotic Murders
2399 Evil Under the Sun (1941)
2499 Five Little Pigs (1942) also published as Murder in Retrospect
2599 The Hollow (1946) also published as Murder after Hours
2699 The Labours of Hercules (1947, ss)
2799 Taken at the Flood (1948) also published as There Is a Tide
2899 The Under Dog and Other Stories (1951, ss)
2999 Mrs McGinty's Dead (1952) also published as Blood Will Tell

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Some Poirot adventures were later expanded into other stories or re-written. They are:
• The Plymouth Express (1923 short story) was expanded into the 1928 novel The Mystery of the Blue Train
• The Market Basing Mystery (1923 short story) was expanded into the 1936 novella Murder In The Mews
• The Submarine Plans (1923 short story) was expanded into the 1937 novella The Incredible Theft
• Christmas Adventure (1923 short story) was expanded into the 1960 novella The Adventure of the Christmas Pudding
• The Mystery of the Baghdad Chest (1932 short story) was expanded into the 1960 novella The Mystery of the Spanish Chest
• The Second Gong (1932 short story) was expanded into the 1937 novella Dead Man's Mirror
• The Regatta Mystery (1936 short story) was re-written in 1939 featuring Parker Pyne instead of Poirot
• Yellow Iris (1937 short story) was expanded into the 1945 novel Sparkling Cyanide featuring Col. John Race instead of Poirot
• Hercule Poirot and the Greenshore Folly (posthumous novella ) expanded into the 1956 novel Dead Man's Folly
• The Incident of the Dog's Ball (posthumous short story) expanded into the 1937 novel Dumb Witness
• The Capture of Cerberus (posthumous short story), originally intended to be the last of The Labours of Hercules but re-written due to its political content
Other stories were adapted by Christie into plays, sometimes removing Poirot:
• Alibi (1928 play) written together with Michael Morton
• Wasp's Nest (1937 TV play)
• The Yellow Iris (1937 radio play)
• Appointment with Death (1945 play) in which Poirot doesn't appear
• Hidden Horizon (1944 play) in which Poirot doesn't appear
• The Hollow (1951 play) in which Poirot doesn't appear
In addition, the 1930 play Black Coffee was novelized by Charles Osborne in 1998.