Anthocyanin is the pigment that gives color in plant. Anthocyanin was extracted from plants to be manufactured as dyes, food coloring and pharmaceutical. This is because anthocyanin is an antioxidant agent. Mangosteen and dragon fruit were believed to contained the anthocyanin based on their color. This research is about comparison of anthocyanin content in mangosteen (Garcinia mangostana Linn) and red dragon fruit ( hylocereus polyrhizus). The content of anthocyanin in both fruits was measured by using pH Differential Method. To use this method, anthocyanin must be extracted from peels of these fruits. Extraction of this anthocyanin then was diluted in different pH of buffers and the reading of absorbance has taken. This step is very important to calculate the exact anthocyanin content in the samples. There also changes in color during diluting the anthocyanin in different pH of buffer. The result showed the mangosteen sample has high reading of absorbance compared to dragon fruit sample. From this data, the mangosteen sample contained more anthocyanin molecules compared to red dragon fruit sample. The calculation from pH Differential method showed that average of anthocyanin content for mangosteen samples was 75.50 mg/L and average of anthocyanin content for dragon fruit was 38.825 mg/L. this result showed that anthocyanin content in the mangosteen was higher compared to red dragon fruit.