Following induction by auxin treatment, the rooting performance oi Elaeis guineensis Jacq. shoots obtained through in vitro clonal propagation by somatic embryogenesis varies considerably. This study involved a preliminary evaluation of guaiacol-peroxidase activity as a marker of in vitro rooting. It was carried out on 17 different clones obtained through a large-scale micropropagation procedure. No rooting occurred in the absence of exogenous auxins. Peroxidase activity evolved as previously described on other species, peaking between 10 and 14 days under optimum initiation conditions. The peak was found to shift in time when the rooting success rate was low. Peroxidase activity measurements, carried out prior to induction on 24 production batches belonging to 13 different atonal lines, revealed a significantly greater heterogeneity in batches with a low rooting success rate (< 50%). Several improved protocols aimed at optimising the rooting phase under large scale propagation conditions are proposed.