The effects of salt stress on the production of ethylene in leaves of five rice cultivars differing in salinity tolerance were investigated after 15 and 30 days of stress exposure in plants sprayed every 2 days with deionised water or putrescine 100 μM. NaCl induced an increase in ethylene synthesis which was higher in salt-tolerant than in salt-sensitive cultivars (cvs.). Salt-stress also induced an increase in 1-aminocyclopropane-1-carboxylic acid (ACC) content which was larger in salt-tolerant cvs. whereas a decrease in ACC conversion to ethylene suggested a reduction in ACC oxidase activity. Putrescine increased the growth and the leaf tissue viability (as indicated by the reduction of 2,3,5-triphenyltetrazolium chloride (TTC) to formazan) of salt-treated plants in all cvs. This positive effect was associated with an increase in ethylene biosynthesis through an increase in ACC content and a suppression of NaCl-induced inhibition of ACC conversion to ethylene. These data suggest that putrescine could be involved in salinity tolerance in rice.