This paper reports hydrodynamics of a laboratory-scale fluid catalytic cracking (FCC) stripper. The laboratory-scale stripper was designed by geometrically and dynamically scaling down an industrial-scale FCC stripper that had a disk and donut baffle. The solids holdup was measured using a γ-ray densitometry technique with a 3-μCi-strength Cs-137 radioactive source. Measurements were taken at different elevations and chordal positions. The effect of operating conditions on the solids holdup profileswasinvestigated indetail.Forexample,theparticle flowrate wasvariedfrom0.025 kg/s to0.042 kg/s,andthesuperficial air velocity between 0.74 m/s and 1.1 m/s. It was observed that the shape of baffles played an important role in the hydrodynamics of the stripper. Several dead zones were noticed under the baffle regions indicating unused areas in the stripper. The measured solid holdup radial profileswere ofasymmetric nature underlyingthe need forthree-dimensional(3D) simulations.At low superficial gas velocities, there was a widespread segregation in the solid phase, which along with the solid holdup decreased on increasing the air superficial velocity. However, the change in solid flow rates did not have any effect on the solids holdup.