Concentration distribution of solid particles in two-phase turbulent pipe flow was studied. Due to the inertia of solid particles, transport of solid particles across the velocity field of the turbulent stream by turbulent diffusion results in deceleration of particles in the region near the wall by the stream and acceleration of particles transported toward the high velocity core. In the core, the particles have lower mean velocity than the stream while near the wall the mean particle velocity is higher. This gives rise to a non-uniform distribution of solid particles in fully developed turbulent pipe flow. Experimental determination of concentration distribution was made with an impact disk particle counter system.