Sweet chestnut is considered to be an extremely difficult-to-root species and the main reason has not yet been understood. There is a lack of knowledge about the method of metabolising free endogenous indole-3-acetic acid (IAA) during the early stages of the adventitious root formation (ARF) process. The present study brings some important insights in the understanding of poor rooting success of chestnut and emphasizes the use of terminal types of cuttings. The time-course level of free IAA was studied in an experiment with terminal and basal leafy cuttings of two hybrid (Castanea crenata × Castanea sativa) sweet chestnut cultivars, Marsol and Maraval. The experiment was set in an unheated plastic house using a fog system for achieving sufficient relative humidity during propagation period. Only free IAA could be determined in cutting bases immediately after severance. In some other woody species also some other IAA metabolites (IAA-Asp, OxIAA, indole-3-methanol) have been presented in previous experiments as possible important substances during ARF. These metabolites in chestnut in our experiment could not be determined. Chestnut cuttings generally accumulated low amounts of free IAA in their bases, with values between 11 ng g^-1 to nearly 50 ng g^-1. The profile of free IAA differed between terminal and basal cuttings, regardless of the analysed cultivar, whereby terminal cuttings on average developed qualitatively a better rooting system, with significantly higher number of main roots. The initial IAA concentration tended to higher values in basal cuttings of the ‘Maraval’. Cuttings of the ‘Maraval’ rooted significantly better compared with ‘Marsol’ cuttings but the initial IAA concentration tended to yield higher values only in basal cuttings of the ‘Maraval’.