A tobacco microsomal ω-3 fatty acid desaturase gene (NtFAD3) under the control of CaMV35S promoter was introduced into rice plants by the microprojectile-mediated transformation. The transgenic plants grew normally and showed high seed fertility and characteristics similar to those of non-transgenic plants. However, the fatty acid compositions in leaves, roots and seeds were modified by the transformation. The content of linoleic acid (18:2) was lower in the transgenic plants than in the non-transgenic plants. However, the content of linolenic acid (18:3) in the root and leaf tissues was, respectively, 1.8- and 1.1-fold higher in 4 transgenic plant lines of the homozygous R₃ progenies, than in the non-transgenic plants. The 18:3 content in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) that are the components of the extrachloroplast membrane, in the leaves of mature plants was higher in transgenic plants than in the non-transgenic plants. Thus, NtFAD3 was expressed and it desaturated 18:2 to 18:3 in the endoplasmic reticulum in rice cells.