Pelargonidin glucoside is a predominant pigment in strawberry fruit and usually followed by cyanidin glucoside (CG). But a considerable amount (5-30% of total anthocyanins) of pelargonidin malonylglucoside (PMG) occurred in the half of Japanese cultivars, such as 'Fukuba', 'Hokowase', 'Nyoho' or 'Tchiotome', and its amount often exceeded CG. On the contrary, 'Toyonoka', 'Ai-berry' or 'Sachinoka' lacked PMG.Inheritence of PMG synthesis in strawberry fruit was investigated using some Japanese cultivars. Selfed progenies of a PMG producing cultivar 'Nyoho' segregated in a 3:1 ratio for occurrence or absence of PMG (P=0.50-0.25), while those of 'Ai-berry' and Toyonoka' lacking PMG, did not segregate PMG producing plant, and Fl hybrid between 'Nyoho' and 'Ai-berry' did in 1:1 (P=0.50-0.25). These results indicate that the production of malonylated anthocyanin in strawberry is controlled by a single dominant gene. According to the pedigree record, it was supposed that almost all Japanese cultivars producing PMG, are genetically heterozygous in this locus. Although the occurrence of PMG has not been confirmed for newly released cultivars, PMG producing gene in homozygous condition may have unfavorable effect on fruit production or something others. Highly significant relationships were found between the total amount of anthocyanins and fruit color, such as chroma, hue and value, while no significant effect of PMG on fruit color could be found.