Antibodies reacting to specific cell surface markers can be bound to magnetic beads and used to specifically capture cells exhibiting the marker. This approach allows the selective enrichment of specific cell subpopulations and as the methods are amenable to use in blood, tissue fluids and culture medium living cells can be recovered that can subsequently be subcultured. Negative cell separation can also be used where undesirable cell types are tagged using magnetic beads and removed from the desirable cell population.