Abstract As a continuation of our studies of cosmic ray (CR) ionization in the atmospheres of the planets in the Solar system [Adv. Space Res. 27 (11) 1901, 2001a] we present a new method for the calculation of the electron production rate q( h) profiles due to particles of all energy intervals: galactic CR, anomalous CR component and other types of high energy particles. In the above mentioned paper, ionospheres of terrestrial planets are investigated, where the spherical model is used. For giant planets which have significant oblateness in spite of the isotropic penetration of the galactic CR in their atmospheres, the trivial integration on the azimuth angle is not applicable, because of the presentation of the planets as rotational ellipsoids and the azimuth dependence of the integrand function. The difference between profiles for spherical q S and ellipsoidal q E models of the terrestrial planets (Earth, Venus and Mars) is small. These differences in the q S and q E profiles increase significantly in the upper atmospheric layers of outer major planets. This requires the introduction of a modified Chapman function for oblate planet in the particle depth parameter (PDP), while considering the CR influence and ionization processes in the ionospheres of the giant planets. New calculations for relative profiles q E/ q S in the atmosphere of Saturn are presented. For this purpose an improved primary CR spectrum with a new type of smoothing function f with tangens hyperbolicus is used.