In this paper we calculate the Hawking temperature of a black hole described by the Kerr-Newman metric, starting from the surface gravity, the area of the event horizon and the angular velocity of the black hole. To do this we apply the laws of black hole thermodynamics: we first set the energy conservation through a relationship between the mass M, the charge Q and the angular momentum J, then we implement the Hawking's theorem of areas by setting an upper bound to the energy and we get finally the surface gravity of the black hole. In addition, we study the relationship between the black hole parameters (mass M, angular momentum J, electric charge Q) and the Hawking temperature.