The objective of the present study was to evaluate sphingolipid levels (sphingosine-So and sphinganine-Sa) and to compare the Sa/So ratio in liver, serum and urine of Wistar rats after prolonged administration (21 days) of fumonisin B-1 (FB1). In parallel, the kinetics of sphingolipid elimination in urine was studied in animals receiving a single dose of FB1. Prolonged exposure to FB1 caused an increase in Sa levels in urine, serum and liver. The most marked effect on sphingolipid biosynthesis was observed in animals treated with the highest dose of FB1. Animals receiving a single dose of FB1 presented variations in Sa and So levels and in the Sa/So ratio.