Isotactic polypropylene stabilised with fullerene [C60], its adduct with methyl levopimarate, carbon black, p-t-butylealix[4]arene, p-t-butylcalix[6]arene, Irganox 1076 or Topanol OC was investigated by means of oxygen uptake method under isothermal (165degreesC) and isobaric (normal pressure) conditions. Oxidation investigations were performed in air as degradation environment. Additive concentration was 0.25 % (w/w). Kinetic parameters, oxidation induction and oxidation rate are compared with similar characteristics of additive-free i-PP. Effect of gamma-irradiation on thermal oxidation is also presented. Three gamma-exposure doses (50, 100 and 150 kGy) were selected. The influence of radiation treatment on the efficiency of studied compounds and some mechanistic aspects are also presented.