Genetic variations in Ranunculus cantoniensis DC. were examined using RAPDs on eight populations from Korea and two individuals from Japan, and compared with previous karyological results. They were clearly separated into two groups by the UPGMA and the UPGCM phenograms. One group coincided with the Atsuki group and the other with the Matsuyama group of karyological data. RAPDs analyses showed that genetic differentiation within the species was more extensive in the Matsuyama group than in the Atsuki. Karyology and RAPDs analysis were very useful in illustrating intraspecific populational differentiation among R. cantoniensis.