ABSTRACT During the last decade, several strategies have been used to produce protoporphy- rinogen oxidase(Protox)-inhibiting herbicide-resistant transgenic plants by using the heterologous overexpression of Protox genes from Bacillus subtilis, Arabidopsis thaliana, Homo sapiens and Myxococcus xanthus. These target genes had been aimed to express in either chloroplasts or mitochondria of various plants via Agrobacterium tumefaciens transformation technology. Among them, best results have been achieved either by using a mutant form of A. thaliana Protox or by employing a natural form of M. xanthus Protox in which the former is a resistant enzyme against Protox-inhibiting herbicides whereas the latter is a sensitive enzyme against Protox-inhibiting herbicides. This review will describe the progress of transgenic plants against Protox-inhibiting herbicides in view of transgenic rice plants expressing various sources of Protox genes. Key words: protoporphyrinogen oxidase-inhibiting herbicides; transgenic plants.