We report the changes in polyamine titres during the Agrobacterium-mediated transformation of rice calli and their influence on plant regeneration capacity following the introduction of putrescine biosynthesis gene ornithine decarboxylase ( odc) as well as β-glucuronidase ( gus) reporter gene. Free polyamine titres increased during the Agrobacterium infection and a general increase in the polyamine titres was seen during early stages of selection. The changes in polyamine levels reflective of the transgene expression emerged late during selection and continued during the regeneration from the calli. An increase in the putrescine titres was observed during regeneration and was found to be helpful for regeneration. These results suggest that polyamine metabolism responds to transformation as well as transgene expression and provided a tool for improving the regeneration from transformed rice calli by modulating polyamine metabolism.