The conditions for the analysis of transformed products of acrylonitrile via micro-oganism by HPLC have been studied. Under these conditions, the transformed products, acrylic acid (AA), acrylamide (AM) and acrylonitrjle CAN) were separated completely. The analytical conditions are μ-Bondapak C18 column and CH3OH-H2O(15:85) eluent. The analytical repro-ducibility was very good. When AUFS was 0.1, the minimum detectable amounts of AA, AM and AN were 2×10-(?)g, 2X10-l0g and 2×10-9g respec tively.