ABSTRAKKulit labu kuning ( Cucurbita moschata ) yang selama ini dianggap sebagai limbah ternyata memiliki manfaat antara lain sebagai antibakteri, antioksidan, karena senyawa metabolit sekunder yang dikandungnya. Salah satu senyawa metabolit sekundernya adalah flavonoid. Penyarian senyawa aktif dalam bahan alam dapat dipengaruhi oleh konsentrasi pelarut. Tujuan penelitian ini adalah mengetahui kadar flavonoid total ekstrak etanol kulit buah labu kuning berdasarkan perbedaan konsentrasi pelarut etanol. Tahapan penelitian meliputi penentuan tanaman, pengumpulan bahan baku, pembuatan simplisia, penetapan kadar flavonoid total secara spektrofotometri UV-Vis. Variabel bebas pada penelitian ini adalah variasi konsentrasi etanol 70% dan 95%, variabel ikatan berupa kadar flavonoid total, variabel kontrol berupa metode ekstraksi, tempat pengambilan sampel. Analisis data yang digunakan adalah analisis deskriptif. Hasil penelitian menyatakan persen rendemen ekstrak etanol 70% dan 95%, masing-masing adalah 13,68% dan 15,54%. Kadar flavonoid total dari ekstrak etanol 70% dan 95%, masing-masing sebesar 1,1931% ± 0,0810; dan 1,2045% ± 0,0854. Sehingga dapat disimpulkan bahwa konsentrasi pelarut etanol berpengaruh terhadap kadar rendemen dan ekstrak flavonoid kulit buah labu kuning.Kata kunci : Cucurbita moschata , flavonoid, konsentrasi pelarut, spektrofotometri UV-Vis. ABSTRACTThe skin of pumpkin (Cucurbita moschata) which has been considered as waste so far has benefits such as antibacterial, and antioxidant, because of the secondary metabolites it contains. One of the secondary metabolites is flavonoids. The Extraction of active compounds in natural products can be affected by solvent concentration. The purpose of this study was to determine the total flavonoid content of the ethanol extract of pumpkin peel based on differences in ethanol solvent concentration. The stages of the research included plant determination, raw material collection, simplicia manufacture, extraction by maceration with variations in ethanol concentration, flavonoid phytochemical screening, and determination of total flavonoid content by UV-Vis spectrophotometry. The independent variable in this study was the variation of 70% and 95% ethanol concentration, the dependent variable was the total flavonoid content, and control variable was the extraction method, where the sample was taken. The data analysis used is descriptive analysis. The results of the study stated that the percent yield of 70% and 95% ethanol extract were 13.68% and 15.54%, respectively. The total flavonoid content of 70% and 95% ethanol extract, respectively, were 1.1931% ± 0.0810, 1.2045% ± 0.0854. So it can be concluded that the concentration of ethanol solvent affects the yield and flavonoid levels of pumpkin peel extract.Keywords : Cucurbita moschata, flavonoids, solvent concentration, UV-Vis spectrophotometry.