The concentration levels of biogenic magnetite nanoparticles in transgenic R6/2 Huntington's disease (HD) mice have been investigated, using seven control and seven HD mice each from an 8 week-old litter and from a 12 week-old litter. Hysteresis and isothermal remnant magnetisation data were collected on a SQUID magnetometer, and analysed using a model comprising dia/paramagnetic, ferrimagnetic and superparamagnetic contributions, to extract the magnetite and ferritin concentrations present. It was found that magnetite was present in both superparamagnetic and blocked states. A larger spread and higher concentration of magnetite levels was found in the diseased mice for both the 8 week-old and 12 week-old batches, compared to the controls.