In this work, the kinetics of coupled aggregation and sedimentation processes arising in magnetic fluids has been studied. Aggregation was induced applying a constant uniaxial magnetic field. The time evolution of the cluster-size distribution and the weight-average chain length was monitored using optical microscopy and digital image analysis. The experimental results are compared with the corresponding solutions of Smoluchowski’s equation. For this purpose, a recently proposed aggregation kernel was employed. When sedimentation effects are taken into account, the fits improve especially at long aggregation times.