The problem of whether cultivars of Brassica spp., Raphanus sativus or Cucurbita spp, could be determined by using the electrophoretic patterns of seed protein or seed enzymes as taxonomic criteria was studied.For the preparation of protein samples, five grams of seeds were ground in a pestle and then mixed into 20ml of a phosphate-buffered saline solution. Extraction proceeded overnight in a refrigerator; then the gruel was centrifuged, the supernatant filtered clear and adjusted to pH 8.0 with 0.1M KOH. The solution was placed in a refrigerator for one hour and then centrifuged. The supernatant was freeze-dried, and the prepared protein was stored dry at -20°C. For the preparation of enzyme samples, one gram of seeds was ground in a pestle and then mixed into four to six ml of a phosphatebuffered saline solution. Extraction proceeded two hours in a refrigerator; then the gruel was centrifuged and the supernatant was freeze-stored at -20°C.Electrophoresis was carried out with acrylamide gel disc.The results are summerized in Table 1.1. Brassica species: Protein, peroxydase, LDH, esterase., acid phosphatase, ADH, GDH and CA were available for the determination of species of Brassica crop seeds. However, none of these electrophoretic patterns could support a conclusive determination for each species, and it was necessary to use at least two to three kinds of electrophoresis for the full determination.Electrophoretic zymograms of peroxydase of B. nigra, Ba juncea and B. carinata were similar to one another, suggesting that these reactions were controlled by a genom b which these species possessed in common.No difference of electrophoretic patterns of protein and enzymes was observed among cultivars in each species. It was considered from this experiment that Chinese cabbage, turnip, Pak-choi, etc, had better be included in one species, that is, B. campestris, rather than be separated respectively into B. pekinensis, B. raga, B. chinensis, etc.2. Radish: No difference of electrophoretic patterns of seed protein and enzymes was observed among cultivars or groups of cultivars of radish.3. Cucurbita species: For the separation of species only two kinds of electrophoresis were available, and they each detected only one species among the four species. Protein patterns separated C. pepo from the other four species and esterase patterns separated C. ficifolia from the other four species. It was impossible forC. moschata, C. maxima and Fl of these species to be separated from one another with their electrophoretic patterns.