Two new fumonisins, hydroxylated fumonisin C1 (1) and fumonisin C3 (3), were isolated from wheat cultures of Fusarium oxysporum together with known fumonisin C1 (2) and C4 (4). Compound 1 is structurally similar to 2 except for the presence of an additional hydroxy group at C-3. Compound 3 is similar in structure to fumonisin B3 except that the C-1 terminal methyl group is missing.