The early diagnosis of tumors, i.e. the detection in biological liquids of low concentrations of tumor markers or cells, is a challenge that can be tackled by developing magnetic-fluorescent nanotools for cell/tumor marker sorting. A magnetic-fluorescent nano-system would perform at the same time separation and detection of cells or analytes while its nanoscale size would offer higher surface to volume ratio, thus higher sensitivity should be achieved. In this view we have recently reported a procedure to cluster superparamagnetic nanoparticles into polymer nanobeads. The diameter of the nanobeads can be controlled in a wide range between 40 and 400 nm. As a further step, we have now developed a procedure to aggregate together magnetic iron oxide nanoparticles and fluorescent quantum dots.