Aim To develop a biocompatible cobalt ferrite (CF-NP) nanodrug formulation using oleic acid and poly (d,l-lactide-co-glycolic) acid (PLGA) for the delivery of docetaxel (DTX) specifically to breast cancer cells. Methods The CF-NP were synthesised by hydrothermal method and conjugated with DTX in a PLGA matrix and were systematically characterised using XRD, FE-SEM, TEM, DLS, FTIR, TGA, SQUID etc. The drug loading, in vitro drug release, cellular uptake, cytotoxicity were evaluated and haemolytic effect was studied. Results The CF-NP showed good crystallinity with an average particle size of 21 nm and ferromagnetic nature. The DTX-loaded CF-NP (DCF-NP) showed 8.4% (w/w) drug loading with 81.8% loading efficiency with a sustained DTX release over time. An effective internalisation and anti-proliferative efficiency was observed in MCF-7 and MDA-MB-231 breast cancer cells and negligible haemolytic effect. Conclusion The DCF-NP can have the potential for the effective delivery of DTX for breast cancer treatment.