The effects of incubation time, temperature, medium volume, and initial pH on the production of territrem B (TRB) by Aspergillus terreus CCRC 32111 were investigated. At 28°C, maximal TRB production and mycelial growth were seen after 12 days’ incubation in potato-dextrose (PD) liquid medium. Greatest TRB production occurred after rapid depletion of available carbohydrate at the stationary phase of fungal growth. TRB production decreased when the broth volume/culture container volume ratio increased, but increased if initial pH was alkaline. These results show that the TRB production is affected by factors including incubation time, temperature, medium volume, and the initial pH of medium.