Fumonisin B-1 (FB1) and B-2 (FB2) production of Fusarium moniliforme isolates (Fm8, Fm22, Fm29, Fm31) on corn kernels and liquid culture and biocontrol activity of two Trichoderma harzianum strains (T16, T23) against mycelial growth and FB1 and FB2 production was evaluated. Fm31 was determined as the highest yielding isolate for fumonisins production (FB1:118.00 mu g/g; FB2:71.67 mu g/g) on corn kernels. It was then incubated in five different liquid culture and the highest concentration of FB1 was obtained from corn meal medium (CMM), with 3.7 initial pH. FB1 amount was as much as on the solid culture, but FB2 amount was noticeably lower. T16 and T23 decreased radial extension of Fm31 about 70% after 13 days. The colony diameter of F. moniliforme was less at 13 days than at 7 days, possibly due to mycelial lysis of Fm31. On corn kernels, T23 performed better with an inhibition rate of 92.96% (FB1) and 92.68% (FB2) at same-day inoculation. In CMM, treatments at 0, 3 and 5 days after inoculation (DAI) of Fm31 rapidly inhibited FB1 and FB2 production. The inhibitory effect of T16 and T23 isolates on fumonisin production could be measured with inoculations at 7 DAI and T23 was again found more effective.