Summary: We denote by \(\mathcal{Q}(A)\) the set of all matrices with the same sign pattern as \(A\). A matrix \(A\) has signed null-space provided there exists a set \(\mathcal{S}\) of sign patterns such that the set of sign patterns of vectors in the null-space of \(\tilde{A}\) is \(\mathcal{S}\), for each \(\tilde{A}\in\mathcal{Q}(A)\). Some properties of matrices with signed null-spaces are investigated.