Model calculations indicate that the lower ionosphere of Saturn is controlled by photochemical processes, with basic features similar to the Jovian ionosphere. The scale height of the upper ionosphere is large (~3350 km). A peak electron density of ~105 cm-3 2250 km above a 1019 cm-3 reference level is expected assuming an eddy coefficient at the homopause of 1.3¿106 cm2 s-1 and a relatively hot exosphere at 1300 K.