Drug-carrying magnetic nanocomposite spheres were synthesized using Co0.5Zn0.5Fe2O4 nanoparticles and poly (D, L-lactide-co-glycolide)(PLGA) for the purpose of magnetic targeted drug delivery. Magnetic nanoparticles (MNP) (~10 nm) were prepared by a chemical co-precipitation of Sulphate salts in the presence of sodium hydroxide. Oil-in-oil emulsion/solvent evaporation technique was conducted at 7000 rpm and 1.5-2 hrs agitation for the synthesis of nanocomposite spheres. Specifically, PLGA and the cancer drug 5-Fluorouracil were first dissolved in Acetonitrile (oily phase I) and combined with MNP. The drug, MNPs and polymer solution was added drop-wise into viscous paraffin oil combined with Span 80 (oily phase II). 10%, 15% and 20% of MNP in the nanocomposite spheres were evaluated in terms of particle size, morphology and magnetic properties using X-ray and SQUID, Fluid flow and Biological trials were carried out to determine their effectiveness in targeted drug delivery.