Structural properties of MnS have been studied using plane wave pseudopotential density functional theory as implemented in Quantum Espresso code. Local density approximation (LDA) along with ultrasoft pseudopotential has been used for total energy calculations. The calculated total energies are fitted to Murnaghan equation of state to calculate equilibrium lattice constant, isothermal bulk modulus and pressure derivative of isothermal bulk modulus for NaCl-type structure of MnS and compared with previous experimental and theoretical calculations and good agreement is achieved with those results. Phonon frequencies have also been derived for B1 phase of MnS along high symmetry directions using the density functional perturbation theory at ambient condition.