Diabetes can cause many complications in the human body. The disease is commonly diagnoses invasively using blood glucose test. A good correlation between blood glucose and exhale breathe acetone has opened a way for non-invasive diagnosis through the detection of the breath acetone from the exhale breathe. However, the conventional means of detecting exhale breathe acetone (e.g. GC-MS) are bulky, require technical knowhow, do not offer real time measurement and found only at advanced institutions that can afford the equipment. This work is aimed at developing a real time, sensitive and selective optical based Surface Plasmon Resonance (SPR) breath acetone biosensor for non-invasive monitoring and screening of diabetes. The motivation of this work arises from the promising advantages of optical based biosensors over other biosensors. Additionally, a novel doped polyaniline (PANI) conducting polymer would be the SPR metallic layer while Chitosan would be the selective sensing layer. Mathematical modeling and SPR simulation has been conducted. The result has shown that the replacement of conventional gold or silver SPR layer with doped Polyaniline (PANI) SPR layer provides better promising sensitivity at mid infrared wavelength range. Therefore, additional inclusion of chitosan layer on the proposed SPR based biosensor would give rise to a sensitive and selective breathe acetone biosensor for easy monitoring and screening of diabetes. © Published under licence by IOP Publishing Ltd.