25 Mg NMR spectra and nuclear spin-lattice relaxation time, T1, have been measured in polycrystalline MgB2 with a superconducting transition temperature Tc = 39 K in zero magnetic field. From the first order and second order quadrupole perturbed NMR spectrum a quadrupole coupling frequency νQ = 222.0(1.5) kHz is obtained. T1T = 1090(50) sK and Knight shift Kc = 242(4) ppm are temperature independent in the normal conducting phase. The 25 Mg Korringa ratio equals to 0.95 which is very close to the ideal value of unity for s-electrons. The comparison of the experimental νQ, T1T , and Kc with the corresponding values obtained by LDA calculations shows an excellent agreement for all three quantities.PACS numbers: 74.70. Ad, 74.25.Jb, 74.25.Nf, 76.60.Cq, The recent discovery of superconductivity in MgB 2 with remarkably high T c = 39 K [1] has attracted much attention. In particular the observation of a sizeable boron [2] isotope effect strongly suggests that this simple layered intermetallic compound belongs to the conventional family of phonon mediated BCS superconductors. The relevant electron-phonon coupling constant is proportional to the density of states (DOS) at the Fermi level. So it is important to have experimental data of this quantity in MgB 2 .Nuclear magnetic resonance (NMR) in metals probes the DOS at the Fermi level. The measured quantities, the spin lattice relaxation rate, 1/T 1 , and the Knight shift, K, are related to the electron spin susceptibility (χ(q, ω)) of electrons close to the Fermi level, specifically 1/(T 1 T ) ∝ lim ω→0 q Imχ(q, ω)/ω, and K ∝ Reχ(0, 0). In case the atomic site symmetry in the crystal structure is less than cubic and the atom has a nuclear quadrupole moment as it applies for Mg and B in MgB 2 , quadrupolar disturbed NMR delivers in addition valuable information on the electric field gradient (EFG) at the specific nuclear site. Unlike 1/T 1 and K the EFG is determined by the distribution of all charges. Up to date only measurements of 1/T 1 , K, and of the quadrupole coupling to the EFG, expressed by quadrupole coupling frequency ν Q , of 11 B were performed [3,4,5,6]. While there is reasonable agreement among 11 B ν Q 's and relaxation rates, there is a considerable controversy concerning the 11 B Knight shifts. While some authors [4] report in the normal conducting state a small temperature independent isotropic shift of 175 ppm, others [5] report a smaller and even temperature dependent shift of approximately 60 ppm, which they attribute to the Fermi-contact interaction. Finally there is also a report [6] of a negative 11 B shift of mere 5 ppm attributed to the core polarization. These large discrepancies most likely come from the choice of * Electronic address: mali@physik.unizh.ch different materials as references for the Knight shift, as well as from difficulties to measure the small 11 B Knight shift of a broad and in addition quadrupolarly shifted 11 B central line powder spectrum.As far as we know, there are no experimental data concerning the NMR quantities at...