We study existence and stability properties of ground-state standing waves for two-dimensional nonlinear Schrödinger equation with a point interaction and a focusing power nonlinearity. The Schrödinger operator with a point interaction (−∆α) α∈R describes a one-parameter family of self-adjoint realizations of the Laplacian with delta-like perturbation. The operator −∆α always has a unique simple negative eigenvalue. We prove that if the frequency of the standing wave is close to the negative eigenvalue, it is stable. Moreover, if the frequency is sufficiently large, we have the stability in the L 2 -subcritical or critical case, while the instability in the L 2 -supercritical case.