A conditional grammar is a Chomsky grammar with languages associated to its rules such that each rule is applicable only to words in the corresponding language. In this paper the generative capacity of type 0, 1, 2, 2 — λ, 3 grammars with associated type 0, 1, 2, 3 languages will be characterized in terms of the Chomsky hierarchy. We shall prove that the generative capacity of context-free and of regular grammars is increased in this way, while for type-0 and type-1 grammars the generative capacity is not modified. Two other variants of these grammars are shown to be equivalent with them.