Experimental results are reported for cross‐flow migration of solid spherical nylon balls (0.238 cm diameter and volume fractionφ=0.02) in three different mediums carried out under plane‐Poiseuille flow conditions in a perspex slit channel (length=226 cm,width=27 cm,height=3.97 cm). The three different fluids employed for suspensions are pure corn syrup (a Newtonian medium), 0.2 wt% polyacrylamide in corn syrup (a nonshear‐thinning elastic medium), and an aqueous solution containing 2.5 wt% polyacrylamide (a shear‐thinning elastic medium). Gamma radiation technique is used to monitor the distribution of nylon particles in the transverse direction at four altitudes of 0.35, 0.7, 1.05, and 1.4 cm, respectively from the top of the slit channel. Measured profiles and visual inspection indicated different flow patterns in the three fluid mediums studied. In the Newtonian medium, particle distribution was found to be uniform, whereas in a nonshear‐thinning medium, migration tended toward the center line resulting in formation of a narrow core. In the viscoelastic shear‐thinning medium, the solid particles concentration is observed between two altitudes measured at about 0.35 cm from top and bottom sides of the slit channel and at about 0.6 cm from the central axis of the channel. Analysis for these different flow patterns based on the contribution of the elastic and viscous effects is given in terms of the rheological behavior of the carrier fluids.