Dyes are a group of chemicals that have been widely used in various industries, including textile industry. More than half of dyes have a nitrogen-nitrogen double bond structure in their molecules. These dyes are called azo dyes. Research on removing dyes from waster water has been done for decades. Recently, biodegradation using white rot fungi has emerged as an alternative method to traditional physical and chemical means for degradation of the dyes. Even though extensive research has been done to study the degradation of dyes by white rot fungi, the specific mechanism of such degradations, and how factors such as pH, buffer, and temperature can influence the degradation are still not fully understood. This study investigated the influence of buffer concentration, pH, temperature and agitation on fungal growth and fungus ability to decolorize three water soluble dyes. The optimal culture parameters were established and then applied to degradations of five azo dyes. The degradation products were identified by Gas chromatography/mass spectrometry (GC/MS) and High performance liquid chromatography (HPLC). Pathway of the degradations of both dyes and their primary products were proposed.