Penelitian ini bertujuan untuk menganalisis kerentanan sosial ekonomi, dan bangunan fisik masyarakat perkotaan terhadap bencana banjir di Kelurahan Margagiri, Kecamatan Bojonegara Kabupaten Serang Provinsi Banten. Metode yang digunakan dalam penelitian ini metode campuran kualitatif dan kuantitatif. Data yang digunakan data primer dan data sekunder. Data primer dikumpulkan dengan observasi langsung di lapangan dan wawancara berstruktur dengan responden yang dipilih secara random dengan teknik simple random sampling. Wawancara dilakukan terhadap 90 kepala rumah tangga dari total populasi 483 kepala rumah tangga. Sedangkan data sekunder diperoleh dari berbagai dokumen dan instansi terkait yang dianggap berkompeten. Hasil penelitian menujukkan bahwa berdasarkan hasil interpolasi kedalaman banjir yang terkena dampak banjir berada di sebagian besar wilayah bagian timur penelitian dengan kedalaman maksimum 1,5 meter. Berbagai faktor yang dapat menyebabkan banjir, seperti kondisi topografi yang lebih rendah, penyempitan sungai, tersumbatnya drainase dan tersumbatnya saluran sungai yang menyebabkan terhambatnya aliran sungai yang mengalir ke outlet utama. Hasil penelitian ini juga menunjukkan bahwa kerentanan sosial ekonomi yang lebih tinggi ditemukan pada tingkat pendidikan dominan yang rendah yaitu tingkat sekolah dasar (SD) (40,42%) dan elemen penduduk rentan karena usia lanjut dan anak-anak sebanyak 30,09 %. Sementara itu, temuan penelitian lainnya berkaitan dengah kerentanan fisik, menunjukkan bahwa tingkat kerentanan tinggi aspek fisik sebanyak 32 bangunan, kerentanan tingkat sedang aspek fisik ebanyak 43 bangunan, dan kerentanan tingkat rendah sebanyak 25 bangunan. Serta tingkat kerentanan sedang hingga tinggi didominasi oleh jenis bangunan non tembok. Kata Kunci: Masyarakat Perkotaan, Kerentanan Sosial Ekonomi, Kerentanan Fisik, Bahaya Banjir ABSTRACT This study aims to analyze the socio-economic and physical building vulnerability of urban communities against flooding in Margagiri Village, Bojonegara District, Serang Regency, Banten Province. The method used in this study was a mixture of qualitative and quantitative methods. The data used were primary data and secondary data. Primary data were collected by direct observation in the field and structured interviews with respondents randomly selected by simple random sampling technique. Interviews were conducted with 90 heads of households from a total population of 483 heads of households. Meanwhile, secondary data were obtained from various documents of related institutions that is considered to be competent. The results of study showed that based on the results of interpolation the depth of floods affected by flooding was in most of the eastern part of the study with a maximum depth of 1.5 meters. Various factors can cause flooding, such as lower topographic conditions, river narrowing, drainage clogging and blockage of river channels which causes obstruction of river flow flowing to the main outlet. The results of this study also showed that higher socioeconomic vulnerability was found at the low predominant level of education, namely elementary school level (40.42%) and elements of the vulnerable population due to old age and children as much as 30.09%. Meanwhile, other research findings related to physical vulnerability, showed that the high level of physical aspect vulnerability was 32 buildings, the moderate level of physical vulnerability was 43 buildings, and the low level vulnerability was 25 buildings. Keywords: Urban community, socioeconomic vulnerability, physical vulnerability, flood hazarrd