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Dr. Weston Lesko is a scientist living in Grayditch in 2277.


Lesko is a determined scientist who performs experiments on fire ants inside Marigold station with a motivation to save the wasteland. However, he is unaware that his experiments are actually destroying it as he does not know his ants are causing destruction. The experiments have proven particularly disastrous for the town of Grayditch, which has been destroyed by the fire ants he created.[Non-canon 1]

Daily schedule

  • Until the quest, Those! is completed, Lesko can be found deep underground in the Marigold station. He will usually be in his laboratory outside the hatchery, or he might flee a short distance into the hatchery itself.
  • Lesko will not return to his shack until Those! is fully completed. This means one must also find a home for Bryan (or refuse to do so) and receive the experience points for this quest before Lesko will return to his shack.

Interactions with the player character

Interactions overview

Icon quest starter.png
This character starts quests.
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This character is involved in quests.
Icon severed ear color.png
This character drops an ear upon death (Contract Killer).


  • Those!: Doctor Lesko requires the Lone Wanderer's help to regain control of his experiment. If the player has a high enough Science skill and Intelligence, an additional dialogue option appears when asking Lesko about his experiments. When the Science option is chosen (60 Science needed), Lesko reveals that he has been using FEV in his experiments. An additional dialogue option will also appear if the player has chosen the perk Entomologist, which upsets the doctor slightly.
  • Nectar Collecting for Fun and Profit: After completion of "Those!", Lesko will pay for samples of fire ant nectar. Be aware that entering Doctor Lesko's shack will be considered trespassing, even though the player might have to enter it to give him some nectar. Stay there for too long, and both the protectron and Doctor Lesko will become hostile.



  • It is evident that Lesko feels little to no remorse about the lives his experiments have cost. He supports the Lone Wanderer's decision to find Bryan Wilks a new home, but only because he will no longer be pestered by Bryan's questions.
  • Lesko can sometimes be killed by fire ants if one leaves both doors to his office open.
  • If the player character does not select the extra payment option during the quest, they cannot obtain Lesko's lab coat. Killing him after completing the quest will net nothing but a loss of Karma. The clothing he has on him is just a normal lab technician outfit.
  • Deciding to wait and get the perk later to use the bonus to Perception or Strength to get 10 in all attributes, if completing 'Those' when the Doctor has returned to his shack, one is no longer able to get the perk as the speech option is now gone.
  • Despite his disregard for human life which caused the deaths of five bystanders, and his lack of sympathy towards the orphaned Bryan, he is considered by the game to have good Karma.

Notable quotes


Weston Lesko appears only in Fallout 3.

Behind the scenes

  • In a 2019 interview, Lesko's voice actor, Mike Rosson, stated that he channeled Frank Grimes from The Simpsons for his performance.[Non-canon 2]
  • Dr. Lesko shares his name with the protagonist of the 1974 environmental horror film Phase IV which features scientists in a battle against mutated ants.



  1. Fallout 3 Official Game Guide Game of the Year Edition p.69: "Doctor Lesko
    Lesko is a somewhat befuddled and misguided scientist whose experiments on ants have proven disastrous for Grayditch. Deep inside Marigold Metro Station, he carries out his research, completely oblivious to the destruction that his Fire Ants have caused. He has little patience for anything beyond his scientific acumen and dismisses his failures as only temporary obstacles on the road to success. While his motivation is to save the Wasteland, his methods are in fact destroying it."
    (Fallout 3 Official Game Guide Game of the Year Edition Wasteland Census)
  2. Ian interviews Mike Rosson (Fallout 3 + 4 Voice Actor): "And Lesko, I'm kind of channeling, Frank, maybe, from The Simpsons a little bit? Whoa!"