A potent itaconic acid producing strain, Aspergillus terreus SKR10, was isolated from horticulture waste. Market refuse, apple and banana, were explored as novel substrates for itaconic acid production with yields of 20 +/- 2.0 and 20.0 +/-1.0 g 1(-1), respectively. Itaconic acid yields of 28.5 +/- 2.2 and 31.0 +/- 1.7 g 1(-1) were obtained with acid and a-amylase hydrolyzed corn starch. The efficiency of itaconic acid production by this wild type strain was improved by ultraviolet, chemical and mixed mutagenic treatments. Two high itaconic acid yielding mutants, N45 and UNCS1 were obtained by gradient plating. These two mutants were capable of producing twice the yield of itaconic acid as the parent strain.