This study investigated the factors controlling behavioural responses of the domestic cat to its prey. Experiment 1 identified three temporally-associated groups of behaviours, and associated these differentialy with killing. Cat behaviours were independent of prey activity. Hunger was not a necessary condition for killing. In experiment 2, I manipulated hunger and the size of the prey. I found that: (1) The probability of a kill increased directly with hunger. (2) When the prey was large or difficult, the probability of a kill decreased. (3) The probability of killing was predictable if the levels of the factors hunger and prey size were known. (4) When these factors were in conflict, cats tended to play with the prey before, after, or instead of, killing. The relevance of these results to other studies of the control of predatory and playful behaviours is discussed.