The influence of carbon and nitrogen sources on the spore yield of T. harzianum in fed-batch culture was investigated. T. harzianum was cultivated in liquid culture media under the effect of different carbon and nitrogen sources at different concentration using a fed-batch process. It was observed that among the various carbon sources studied, glucose (2.5 g l-1) gave the highest spore yield of 2.81±0.14 while starch (15.0 g l-1) gave the lowest spore yield (0.22±0.17). The effect of nitrogen sources revealed that 1.0 g l-1 of casein enhanced the highest spore yield (2.88±0.02) while the lowest spore yield (0.23±0.02) was recorded in medium containing soy meal (9.0 g l-1) preparation. The results revealed that T. harzianum has the ability to utilize various carbon and nitrogen compounds and produce high spore yield at low carbon and nitrogen concentration. This can be considered during industrial production of T. harzianum spores for biocontrol.