I agree with Afcjan, the best for all sizes of cats is the Frontline Spot-On, it comes in measured doses in capsules, so there is no danger of overdosing, especially for kittens. As Afjcan said, you just separate the fur at the back of the neck (base of skull), and apply the small amount of liquid directly on to the skin. The only thing is they advise not stroking the cat for half-an-hour until the fur has dried, and then not to let the kitten/cat sleep on your bed for one night. Elaine is quite right in that if you have actually seen fleas on the kitten, you can use the Frontline spray to spray her basket if she has one, and the carpets. There's no need to worry about fleas falling off the cat, as they will be dead. After spraying carpets, a good vacuuming is all that is necessary. If the routine of Spot-on every 4/5 weeks is kept up, there'll be no further problem with fleas. Hope this helps.