Glycinebetaine is a compound that some plants accumulate as a defence against stress conditions. In this paper we demonstrate that the application of glycinebetaine to cotton seed increased plant yield. Seed germination and seedling vigour in a saline soil were increased by 64 and 68%, respectively by seed treatment with glycinebetaine at 5% (w/w). Cotton yield was increased by 18 to 22% by the seed treatment at 5 and 7.5 % , respectively. Additional foliar application of glycine betaine was beneficial only at low levels of seed treatment.