They were in their early 20s–late 20s when Keeping Up with the Kardashians first premiered in October 2007, with Kendall and Kylie still preteens at the time.

Ages when the show started

When Keeping Up with the Kardashians season 1, episode 1 aired on October 14, 2007, the core family members were approximately the following ages.

  • Kourtney Kardashian – 28 years old.
  • Kim Kardashian – 27 years old.
  • Khloé Kardashian – 23 years old.
  • Rob Kardashian – 20 years old.
  • Kendall Jenner – 12 years old.
  • Kylie Jenner – 10 years old.

The parents on the show at that time were in their 50s.

  • Caitlyn (then Bruce) Jenner – 58 years old.
  • Kris Jenner – 52 years old.

So if you’re rewatching season 1 now, you’re basically seeing Kim in her late 20s, Kourtney as the oldest sibling at 28, and Kylie literally still a kid running around the house.

TL;DR:
Kourtney was 28, Kim 27, Khloé 23, Rob 20, Kendall 12, and Kylie 10 when Keeping Up with the Kardashians began airing in October 2007.

Meta description (SEO):
Wondering how old were the Kardashians when the show started? Here’s the exact age of every Kardashian-Jenner family member when Keeping Up with the Kardashians premiered in 2007.

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