SCIENTIFIC ABSTRACT We propose to make spectroscopic observations of the giant planets (Jupiter, Saturn, Uranus and Neptune) using the LWS and SWS instruments. In addition, some CAM-CVF and PHOT-S observations will be made. The scientific goals are: - To make complete spectral surveys using the SWS and LWS, with additional dedicated observations of particular lines. This will allow the determination of the concentrations of the most important atmospheric species, and will establish a chemical inventory of the atmospheric composition, which will assist in characterising the tropospheric and stratospheric chemistry. - To establish the deuterium:hydrogen (D:H) and helium:hydrogen (He:H) ratios in the atmospheres of the giant planets. This will shed light on their primordial abundances and on the formation of the solar system. - To investigate the transport of material from the deep atmosphere through the tropopause into the stratosphere. - To investigate the effects of clouds on the FIR continuum emission. A full discussion of the scientific case is give in the CP programmes of the LWS Solar System SAG and the Mission Scientists.