Interspecific hybrids are very important breeding materials to introduce new genes from wild species into crop plants. In this study, A. officinalis (2n=2x=20) cv. Mary Washington 500W was crossed with A. schoberioides (2n=4x=40), which is a dioecious species distributed in China, Korea and Japan. We obtained putative interspecific hybrid plants from reciprocal crosses between these two species. Five F1 progenies (A. schoberioides × A. officinalis) were used for cytological and RFLP analyses. The chromosome number of all F1 progenies was 2n=3x=30. The RFLP patterns of chloroplast DNA in the progenies were the same as the pattern of maternal parent, A. schoberioides. Additionally, the RFLP patterns of ribosomal DNA in the progenies shared the fragments specific for both parents. These results suggest that the cytoplasm of putative hybrid plants was derived from the maternal parent and that nuclear DNA of the plant was derived from both parents, showing that these progenies were interspecific hybrids between A. schoberioides and A. officinalis. The morphological characters of five hybrid plants appeared to be mixtures of both parents. Out of five plants, three plants flowered; one was male and two were females. This indicates that these two species seem to have the same mechanism of sex determination.