The present invention relates to methods for separating target cells from non-target cells using immunorosettes and magnetic particles. The method involves contacting a sample containing target cells and secondary targets such as erythrocytes with an antibody composition which allows immunorosettes of the target cells and the secondary targets to form. The sample is subsequently contacted with a second antibody composition which allows the binding of magnetic particles to the formed immunorosettes and free secondary targets. The immunorosettes and secondary targets labeled with magnetic particles are separated from non-target cells using a magnetic field. The antibody composition optionally contains bifunctional antibodies or tetrameric antibody complexes.