We have studied the flow behavior of chemically-conjugated nanostructures consisting of fluorescent PbSe quantum dots coupled with magnetic γ-Fe2O3 nanoparticles,. under viscous flow and an external magnetic field. The γ-Fe2O3 moieties were used to control the trajectories of the nanoplatforms under an external magnetic field in polymers fluids mimicking the viscosity of the bloodstream. The flow was followed by the visualization of the nanoplatform trajectories via a specially-developed image processing package, under various fluid flow rates, viscosities and applied magnetic field strengths. Here we show that even at low magnetic fields (∼1 Tesla), the trajectories of the nanoplatforms can be controlled, fact which validates the fundamental drug targeting and delivery strategy in which magnetic nanoparticles are used as the active targeting constituents, indicating the possibility of a paradigm shift in the area of targeted drug delivery. Copyright © 2010 American Scientific Publishers All rights reserved.