Abstract:This paper studies some factors affecting the anthocyanin content in plantlets of Begonia fimbristipula Hance in vitro, i.e. composition of medium, pH, sugar, riboflavin and coconut milk. The anthocyanin content of the plantlets grown on 1/2 SH of medium was 33% more than that of 1/2 MS. The optilnal pH of medium for anthocyanin content and growth was 5.8. The kinds of sugar had marked effect on the anthocyanin content as the an- thocyanin content of plantlets grown on the medium with D-fructose was hi- gher than that of other sugars having 52% increase than that sucrosr. But, the growth of this medium was very low and equal to about 64% of sucrose.