Biodegradation of triphenylmethane dyes by bacteria, actinomycetes, yeasts, and fungi are discussed in detail. The disadvantages of physical and chemical treatment processes of dye wastewater are also discussed. Biological treatment processes have many advantages over the chemical and physical treatment processes such as possibility of degradation of dye molecules to carbon dioxide and water and formation of less sludge in addition to being environmently friendly. This group of dyes is toxic depending on the concentration used. Toxicity of triphenylmethane dyes is discussed with respect to different organisms. Some aspects of biodegradative products of this group of dyes are also mentioned.