Abstrak. Tanaman serai wangi (Cymbopogon nardus L) merupakan salah satu jenis tanaman wewangian yang memiliki kandungan minyak atsiri yang dapat digunakan sebagai agen antibakteri. Melihat potensi antibakteri yang dimiliki minyak serai wangi, menarik untuk diformulasikan dalam suatu sediaan seperti sabun mandi sehingga dapat membantu meningkatkan nilai guna dari sabun. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan pola non faktorial yang terdiri dari 7 taraf dan 3 ulangan, yaitu konsentrasi minyak serai wangi 0 (M1), 0,5% (M2), 1% (M3), 1,5% (M4), 2% (M5), 2,5% (M6) dan 3% (M7). Analisis terhadap sabun padat transparan yang dilakukan meliputi analisis kimia (kadar air, alkali bebas dan pH), uji aktivitas antibakteri terhadap bakteri Staphylococcus aureus serta uji organoleptik secara hedonik (warna, aroma, kekerasan, transparansi, banyak busa dan after used). Hasil penelitian menunjukkan pada pembuatan sabun padat transparan dengan penambahan konsentrasi minyak serai wangi bepengaruh sangat nyata (P≤0,01) terhadap nilai kadar air, alkali bebas dan pH. Sabun padat transparan tersebut memiliki nilai kadar air 5,78%, kadar alkali bebas 0,36% dan nilai pH 11,42. Sedangkan uji efektivitas antibakteri pada sabun padat transparan minyak serai wangi mampu menghambat bakteri Staphylococcus aureus sebesar 1,64 mm pada konsentrasi 2,5%. Uji organoleptik pada sabun padat transparan minyak serai wangi tidak berpengaruh nyata terhadap warna, aroma, kekerasan, transparansi, banyak busa dan after used. Hasil penelitian menunjukkan bahwa sabun padat transparan  dengan penambahan minyak serai wangi 2,5%  adalah perlakuan terbaik.Quality Characteristic, Organoleptic and Antibacterial Activity Transparent Solid Soap with Addition Citronella Oil Abstract. Citronella plant (Cymbopogon nardus L) is a type of fragrance plant that contains essential oils that can be used as antibacterial agents. Seeing the antibacterial potential of lemongrass oil, it is interesting to formulate it in a preparation such as bath soap so that it can help increase the useful value of soap. This study used a completely randomized design (CRD) with a non-factorial pattern consisting of 7 levels and 3 replications, namely the concentration of citronella oil 0 (M1), 0.5% (M2), 1% (M3), 1.5%. (M4), 2% (M5), 2.5% (M6) and 3% (M7). The analysis of transparent solid soap includes chemical analysis (moisture content, free alkali and pH), antibacterial activity test against Staphylococcus aureus bacteria and hedonic organoleptic tests (color, aroma, hardness, transparency, lots of foam and after use). The results showed that the making of transparent solid soap with the addition of citronella oil concentration had a very significant effect (P≤0.01) on the value of water content, free alkali and pH. The transparent solid soap has a moisture content value of 5.78%, free alkaline content of 0.36% and a pH value of 11.42. While the antibacterial effectiveness test on the transparent solid soap of citronella oil was able to inhibit Staphylococcus aureus bacteria by 1.64 mm at a concentration of 2.5%. Organoleptic test on transparent solid soap of citronella oil had no significant effect on color, aroma, hardness, transparency, amount of foam and after use. The results showed that the transparent solid soap with the addition of 2.5% citronella oil was the best treatment.