Hard-boil the eggs for at least 10 minutes. Drain the eggs and cool them submerged in cold water for 10 minutes. Carefully crack open and peel eggs. Slice the eggs in 1/2 lengthwise, separating the yolks into a small bowl.
Add the mayonnaise, ketchup, and diced pickles to the yolks and mash until consistent. Add salt and pepper to taste, erring on the side of salty side to flavor the egg whites.
Scoop or pipe the filling into the empty white shells. You can cover loosely with plastic wrap and chill in the fridge for up to a day, but bring slightly to room temperature before enjoying.