In the Czochralski growth of GGG/Nd:GGG, the percentage of oxygen flowing in the growth chamber plays an important role in eliminating or controlling a number of growth problems. In this paper we report the growth of Nd3+:Gd3Ga5O12 (Nd:GGG) crystal at different flow rates of argon and oxygen percentages (1-2%) and concluded that the optimum percentage is 1.0-1.2%. No effect on the crystal growth was observed while increasing the argon flow rate from 240 LPH to 420 LPH and by keeping same percentage of oxygen. The growth of Nd:GGG crystal by the Czochralski technique with a flat crystal/melt interface was also studied using different crucible sizes and under the same crystal growth conditions. In this study, it was found that the critical Reynolds number, which measures the flow driven by crystal rotation to achieve flat crystal/melt interface, is directly proportional to the crucible diameter. And the crucible diameter (D) is related with the crystal diameter (d) by equation D=K omega d(2), where K is the proportionality constant and omega is the crystal rotation rate. We also found that for a given crucible, the critical Reynolds number remains the same even for different crystal diameters. (C) 2012 Elsevier B.V. All rights reserved.