A phase doppler particle analyzer (PDPA) was used to measure the liquid/solid two-phase flow pattern in a 25 mm minihydrocyclone. The distributions of velocity, concentration, root mean square (RMS) velocities, and especially the average diameter of the particles were evaluated in this work. The measurements showed that in the upper section of the minihydrocyclone the particles accumulated in the outer helical flow near the line of zero velocity value (LZVV), which probably means that the inner helical flow has a more important influence on the separation. Strong turbulence occurred around the air-core as well as around the zone near the wall. The RMS value indicated that the transformation of the axial flow direction takes place in the lower section of the conical length.