The aim of this paper is to report on a recently developed fully coupled and fully implicit solver for turbulent combustion. All the equationsare written in terms of primitive variables (pressure, velocity, temperature, turbulent parameters and species mass fractions) and solved in a fully coupled manner. The coupled system of equations is solved using an unstructured collocated Finite Volume (FV) approach using a fully implicit temporal discretization. An all speed version of AUSM approach is used along with a time derivative preconditioning. The developed fully coupled solver can be applied to a wide range of flow speeds from incompressible limit to hyper-sonic regimes. For solving the resulting system of equations, a sparse ILU preconditioned, sparse GMRES solver is used. This sparse matrix solver is very effective and only linearly increases the computational cost with increasing number of solution cells and number of solution variables. Turbulence reaction coupling is basically obtained using Eddy Dissipation Model (EDM) approach.