Not necessarily, however, to be on the safe side, since worms can lead to other very serious illnessess if left untreated, get the cats dewormed at the appropriate age. Have your vet deworm them with Strongid when he deems them ready. Hope that helps. (FYI most of the cheap stuff you buy at grocery stores does not worm them properly and can potentionally hurt them...it's much cheaper to have it done by a vetrinarian, it can save you heafty medical bills incase you dose them incorrectly. So i advise your vet deworm them with Strongid just to be safe. Good luck!!