There are four main reasons cats will urinate outside the litterbox. The first is litterbox aversion, meaning that a cat finds her “toilet” unacceptable. Perhaps you only have one litterbox in the house when you should have two (three, if you have two cats). Or maybe you are not using unscented, finely grained litter — a cat’s preferred type. (They evolved in the desert so like to relieve themselves where it feels sandy.) Or maybe the litter is too shallow. All these impediments are easily fixed.