Sclerotinia sclerotiorum is a soil borne plant pathogenic fungus that causative white rot disease in most of vegetable crops, including bean (Phaseolus vulgaris L.). In this study, the effect of different carbon, nitrogen sources and C/N ratios on the growth of S. sclerotiorum were examined. Sclerotia development and sclerotia dry weight were also assayed. The mycelial growth of the fungus was increased with most of carbon sources tested, but the highest levels were found when D-glucose and saccharose were added that produced 1.34 and 1.32 mg/ml mycelial dry weight. Whereas, L-alanine and L-arginin were the best nitrogen sources for the growth of S. sclerotiorum with 0.95 and 0.66 mg/ml mycelial dry weight, respectively. However, ammonium chloride gave moderate growth of the fungus that produced 0.49 mg/ml mycelial dry weight. The best C/N ratios were 9:1 and 20:1 with mycelium dry weight of 1.40 mg/ml in to ratios and 28.75 and 16.25 sclerotium/flask, respectively.