Analysis is made on the heat transfer by a turbulently flowing fluid with suspended small solid particles in a circular pipe. Temperatures in the system are assumed to be less than about 1000 F, so that radiation effects are negligible. The loading ratio of solids to gas based on mass is less than or equal to one in the present investigation. The governing equations for the system are derived as two coupled linear equations. With approximations, the governing equations with their boundary conditions reduce to a form of the corresponding governing equation for the one-phase heat-transfer system. Computations of the solution are accomplished by use of the solutions in one-phase case. The final results are compared with existing experimental data and are discussed.