The nucleation parameters such as critical radius, critical free energy change, and critical free energy barrier have been estimated for L-arginine trifluoroacetate single crystals on the basis of the classical homogeneous nucleation theory. Metastable zonewidth ranging in the extent of 7-10 degrees was determined employing the polythermal method. The induction period measurements were also made and it was observed that the induction period decreases with increase in the supersaturation, and hence the nucleation is more probable for the higher value of supersaturation. Bulk crystals were grown successfully from the optimized growth nucleation parameters. (C) 2008 Elsevier B.V. All rights reserved.