ABSTRAK Kurang gizi pada balita 0-23 bulan masih menjadi masalah kesehatan masyarakat di Provinsi DKI Jakarta. Pada tahun 2017 prevalensi underweight di Provinsi DKI Jakarta tergolong prevalensi medium (14,5%), sementara wasting tergolong serius, sedangkan untuk stunting termasuk rendah (18,1%). Tujuan penelitian untuk mengetahui hubungan antara asupan energi, asupan protein, asupan lemak, keragaman jenis makanan, frekuensi pemberian makanan, ASI eksklusif, inisiasi menyusu dini, penimbangaan berat badan, pemberian kapsul vitamin A, riwayat pendidikan formal ibu dan status ibu bekerja dengan kurang gizi pada Balita 0-23 bulan di Provinsi DKI Jakarta tahun 2017. Kurang gizi diukur menggunakan Compocite Index of Anthropometric Failure (CIAF). Penelitian ini menggunakan desain cross sectional dengan jumlah sampel 658 balita 0- 23 bulan. Hasil penelitian menunjukkan prevalensi kurang gizi pada Balita 0-23 bulan dengan indikator CIAF jauh lebih tinggi (31,9%) dibandingkan dengan indikator BB/U, PB/U, dan BB/PB. Asupan protein, keragaman jenis makanan, pemberian kapsul vitamin A dan status bekerja ibu berhubungan signifikan dengan kurang gizi. Faktor dominan adalah asupan protein. Balita yang mengkonsumsi protein kurang memiliki risiko sebesar 4,8 kali (95% CI: 0.599-38.746) untuk mengalami kurang gizi dibandingkan Balita yang mengkonsumsi protein cukup. Terdapat interaksi antara asupan protein dan keragaman jenis makanan. Interaksi tersebut saling melemahkan terhadap kejadian kurang gizi. Kata kunci: Kurang gizi, balita 0-23 bulan, CIAF, asupan protein Undernutrition in under five children (0-23 months) is still a public health problem in DKI Jakarta Province. In 2017, the prevalence of underweight in DKI Jakarta is classified as medium prevalence (14.5%), while wasting is considered serious, meanwhile stunting is low (18.1%). The objectives of the study were to investigate the relationship between energy intake, protein intake, fat intake, food diversity, feeding frequency, exclusive breastfeeding, early breastfeeding initiation, weight monitoring, vitamin A capsule supplementation, maternal formal education and maternal working status with undernutrition in under five children (0-23 months). Undernutrition was measured using the Composite Index of Anthropometric Failure (CIAF). This research use cross sectional design with number of sample 658. The results showed prevalence of undernutrition using CIAF indicator is much higher (31.9%) compared with BB / U, PB / U, and BB / PB indicators. Protein intake, dietary diversity, vitamin A capsule supplementation and maternal working status were significantly associated with undernutrition. The dominant factor is protein intake. Toddlers who consumed less protein had 4.8 times higher risk (95% CI: 0.599-38.746) to experience undernutrition compared to toddlers who consumed enough protein. There is an interaction between protein intake and food diversity. The interactions are mutually debilitating to the incidence of undernutrition. Key words: Undernutriton, under five children (0-23 months), CIAF, protein intake