Mean density and temperature gradients of solar wind protons and &agr; particles are derived from SWICS/Ulysses observations between 1.2 and 5.4 AU in the ecliptic plane during declining solar activity. All parameters are sorted in solar wind speed classes. The radial gradients show a similar behavior for both ion species. In the slow solar wind protons as well as &agr; particles are found to expand adiabatically all the way out to many AUs, while in the fast wind ions evolve non-adiabatically and are heated by interplanetary sources. The &agr; particle to proton temperature and density ratios are also determined. They do not show any clear radial dependence. ¿ American Geophysical Union 1995.