A numerical study is performed to investigate thermal transport phenomena of the laminarizing flow in a strongly heated circular tube. A k-epsilon turbulence model is employed to determine the turbulent viscosity and the turbulent kinetic energy. The turbulent heat flux is expressed by Boussinesq approximation in which the eddy diffusivity for heat is determined by a t(2)-epsilon(t) heat-transfer model. Both models are slightly modified to improve the accuracy in the turbulent-to-laminar transition region. The governing boundary-layer equations are discretized by means of a control volume finite-difference technique and numerically solved using a marching procedure. Results are obtained for Stanton number, turbulent kinetic energy, temperature variance and velocity and temperature dissipation time scales in laminarizing flow.