Title: The Scooby-Doo Show
Content:  The Scooby-Doo Show is an American animated mystery comedy series. The title of the series is an umbrella term for episodes of the third incarnation of Hanna-Barbera's Scooby-Doo franchise. A total of 40 episodes ran for three seasons, from 1976 to 1978, on ABC, marking the first Scooby series to appear on the network. Sixteen episodes were produced as segments of The Scooby-Doo/Dynomutt Hour in 1976, eight episodes were produced as segments of Scooby's All-Star Laff-A-Lympics in 1977 and sixteen episodes were produced in 1978, with nine of them running by themselves under the Scooby-Doo, Where Are You! name and the final seven as segments of Scooby's All-Stars. Despite the yearly changes in 
Title: Scooby-Doo (character)
Content:  Scooby-Doo character with a sloping chin, spots, a long tail, a sloped back, and bow legs – all traits in direct opposition to those of a prize-winning purebred Great Dane. In defining the personality of the dog, Ruby and Spears looked for inspiration to the characters played by Bob Hope in his horror-comedies – a coward who shows traits of bravery when his friends are in danger. Veteran H-B voice artist Don Messick was the original voice of Scooby and spent decades working on the character. Scooby-Doo, Where Are You! premiered on CBS on September 13, 1969, at 10:30 a.m. Eastern Time. It ran for two seasons, with a total of 25 episodes. Its final first-run episode aired on October 31, 1970.
Title: Scooby-Doo, Where Are You!
Content:  Scooby-Doo, Where Are You! is an American animated mystery comedy television series produced by Hanna-Barbera for CBS. The series premiered as part of the network's Saturday morning cartoon schedule on September 13, 1969, and aired for two seasons until October 31, 1970. In 1978, a selection of episodes from the later series Scooby's All-Stars and The Scooby-Doo Show were aired on ABC under the Scooby-Doo, Where Are You! name, and they were released in a DVD set marketed as its third season. Scooby-Doo, Where Are You! is the first incarnation of a long-running media franchise primarily consisting of animated series, several films, and related merchandise.
Title: Scooby-Doo
Content:  The first episode of Scooby-Doo, Where Are You! "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured Don Messick as Scooby-Doo, Casey Kasem as Shaggy, Frank Welker as Fred, actress Nicole Jaffe as Velma, and Indira Stefanianna as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from The Jetsons (1962–63), also voiced by Messick. Seventeen episodes of Scooby-Doo Where are You! were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks. Each of these episodes features Scooby and 
Title: Scooby-Doo
Content:  The Scooby-Doo characters first appeared outside of their regular Saturday-morning format in Scooby Goes Hollywood, an hour-long ABC television special aired in prime time on December 13, 1979. The special revolved around Shaggy and Scooby attempting to convince the network to move Scooby out of Saturday morning and into a prime-time series, and featured spoofs of then-current television series and films such as Happy Days, Superman: The Movie, Laverne & Shirley and Charlie's Angels. In 1979, Scooby's tiny nephew Scrappy-Doo was added to both the series and the billing, in an attempt to boost Scooby-Doos slipping ratings. The 1979–80 episodes, aired under the new title Scooby-Doo and Scrappy-Doo as an independent half-hour show, succeeded in regenerating interest in the show. Lennie Weinrib voiced Scrappy in the 1979–80 episodes, with Don Messick assuming the role thereafter. Marla Frumkin replaced Pat Stevens as the voice of Velma mid-season.
Title: Scooby-Doo
Content:  Scooby-Doo is an American animated franchise comprising many animated television series produced from 1969 to the present, as well as their derivative media. Writers Joe Ruby and Ken Spears created the original series, Scooby-Doo, Where Are You!, for Hanna-Barbera Productions in 1969. This Saturday-morning cartoon series featured teenagers Fred Jones, Daphne Blake, Velma Dinkley, and Shaggy Rogers, and their talking Great Dane named Scooby-Doo, who solve mysteries involving supposedly supernatural creatures through a series of antics and missteps. Scooby-Doo was originally broadcast on CBS from 1969 to 1976, when it moved to ABC. ABC aired various versions of Scooby-Doo until canceling it in 1985, and presented a spin-off featuring 
Title: Scooby-Doo and Scrappy-Doo (1979 TV series)
Content:  The original thirty-minute version of Scooby-Doo and Scrappy-Doo constitutes the fourth incarnation of the Hanna-Barbera Saturday morning cartoon Scooby-Doo. It premiered on September 22, 1979, and ran for one season on ABC as a half-hour program. A total of sixteen episodes were produced. It was the last Hanna-Barbera cartoon series (excluding prime-time specials) to use the studio's laugh track.
Title: Scooby-Doo! Mystery Incorporated
Content:  The first season of ''Scooby-Doo! Mystery Incorporated'' ran for twenty-six episodes between 2010 and 2011 with an unknown stop to the airing of the episodes after episode thirteen. The first episode of the season premiered as a sneak peek on April 5, 2010, and reaired on July 12, 2010 on Cartoon Network along with the next twelve episodes in the United States. The series continued to air on Canada's Teletoon after episode thirteen. The remaining thirteen episodes, dubbed as a second season by Cartoon Network, began airing on May 3, 2011 until July 26, 2011. During the hiatus the first episode of the second season premiered on March 30, 2012 on Cartoon Network Videos and aired on 
Title: Scooby-Doo! Mystery Incorporated
Content:  Prior to the volume releases the first episode in the series, "Beware the Beast from Below" was released as a bonus episode in the special features of Scooby-Doo! Camp Scare on September 14, 2010. "Menace of the Manticore" was also released as a bonus feature on Big Top Scooby-Doo! on October 9, 2012. Also, "When the Cicada Calls" from Season 1 and "The Devouring" from Season 2 were released on ''Scooby-Doo! 13 Spooky Tales: For the Love of Snack!'' on January 7, 2014. "Night on Haunted Mountain" was also released on ''Scooby-Doo! 13 Spooky Tales: Field of Screams'' on May 13, 2014. Warner Home Video started releasing episodes to DVD on January 25, 2011 in the US. The first three volumes contain 
Title: Scooby-Doo! Mystery Incorporated
Content:  in the UK on June 2, 2012 with four more episodes premiering until June 6, 2012. The official Warner Brothers website announced that the second season would begin airing on Cartoon Network in May 2012 but was set back to July 30, 2012 in the United States. The first fifteen episodes aired on weekdays after July 30, 2012, until August 17, 2012. The show went on another hiatus until March 25, 2013, when the remaining episodes of season two began to air in the United States and concluded on April 5, 2013. Each episode of the series is called a "chapter" in line with the show's overarching story, numbered from 1 to 52 across both seasons.

Question: when was the first episode of scooby doo?
Answer: September 13, 1969.