Dynamic phenomena at liquid-liquid interface during transesterification of corn oil was investigated by using a pendant drop method. The drop volume of corn oil gradually decreased as time proceeds because of the dissolution of the products such as fatty acid methyl ester and glycerol in methanol. The drop volume of corn oil with 10 mol oleic acid was almost constant during first 240 s of the reaction and then decreased. The consumption of KOH during saponification of oleic acid at the interface ceased the transesterification of corn oil. During the saponification, the apparent interfacial tension was initially increased due to the increase in hydrophilicity by transfer of water produced at the interface to methanol phase, and then, decreased due to the dissolution of fatty acid methyl ester formed by the transesterification in both oil and methanol phases. © Published under licence by IOP Publishing Ltd.