The well-known Boolean-law "α → (β → α) = 1" can be generalized to fuzzy context as I(x, I(y, x)) = 1, where I is a fuzzy implication. In this paper we show the necessary and sufficient conditions under which this generalization holds in fuzzy logics. We focus the investigation on the following classes of fuzzy implication: (S, N )-, R-, QL-, D-and (N, T )-implications. In addition, we demonstrate that a fuzzy implication I satisfies such Boolean-like law if, and only if, its Φ-conjugate also satisfies it.