This paper presents a study of turbulent mixing in two-dimensional confined impinging streams. A new composite turbulence model is proposed and verified by comparing its predictions with available experimental impingement heat-transfer data as well as the experimental temperature distributions in impinging streams obtained in this work. Better agreement between experimental and numerical impingement heat-transfer results predicted by this new model is noted compared to those predicted by two other low-Reynolds number k-epsilon turbulence models. The model was then used to perform a parametric study of the thermal mixing characteristics of two-dimensional turbulent confined impinging streams. It is found that both the operating and geometric parameters of the system have strong effects on mixing in impinging streams.