The effects of microwaves (MWs) on the secondary structure of haemoglobin were investigated by means of Fourier Transform Infrared (FTIR) Spectroscopy. A set of samples of 250μl of different hemoglobin aqueous solutions (also in the presence of sucrose, trehalose and NaCl) were exposed for 3 hours to 900 MHz mobile phone MWs at a magnetic field intensity around 18 mA/m. Quantitative spectral analysis revealed significant increases in intensity of amide I and II modes after exposure to MWs for haemoglobin in bidistilled water, but not for hemoglobin in sodiumchloride, sucrose and trehalose aqueous solutions. Indeed, MWs interaction with the a-helix structure increases its dipole moment, produces increases in intensity of amide I and II modes whose major contribution is related to the a-helix content. This effect did not result to be significant for haemoglobin in sodium chloride, sucrose and trehalose aqueous solutions.