Hair dye preparations are cosmetics used in hair makeup to color hair, either to restore the original hair color or change the original hair color to a new color. Kepok banana heart contains dyes and produces anthocyanins which are used as a safe food coloring. The purpose of this study was to determine that the leaf extract of the Kepok banana heart can be formulated as a hair dye and to determine the concentration of the banana flower extract that produces the best color. Kepok banana flower petals were extracted by maceration method using 96% ethanol, then concentrated to obtain Kepok banana flower petals extract. Hair dye preparations were made with a formula consisting of Kepok banana flower petals extract with various concentrations, namely: 2.5%, 5%, 7.5% and 10%. Staining is done by soaking for 1-4 hours. Observation of color stability was carried out by means of a stability test against 15 washings and exposure to the sun for 5 hours on colored hair, and a biological test (irritation). This study showed that the formula made with the extract of the petals of the Kepok banana heart can give a black color. The best staining was obtained from formula C, namely the extract of the petals of the banana heart of the Kepok banana with a concentration of 7.5% which produced a dark black color. The stability test for 15 washes and the stability test against the sunlight for 5 hours showed that there was no discoloration and no irritation to the skin. It can be concluded that Kepok banana flower petal extract can be used as hair dye.