ABSTRAK Penelitian ini bertujuan untuk mengetahui kejadian kolibasilosis pada anak babi berdasarkan kelompok umur. Sebanyak 2005 ekor sampel berupa usap rektal anak babi diambil dari peternakan babi di Kabupaten Badung, Tabanan, Gianyar dan Kodya Denpasar di Provinsi Bali. Seluruh sampel dilakukan isolasi dan identifikasi Escherichia coli (E. coli). Hasil penelitian menunjukkan angka kejadian kolibasilosis pada anak babi sebesar 846 (42%), dan faktor resiko tertinggi kejadian kolibasilosis ini ditemukan pada anak babi berumur antara 0-2 minggu sebesar 62%. INCIDENCE OF COLIBACILLOSIS IN PIGLETS ABSTRACT A study was conducted to know the incidence of colibacillosis in piglets based of age factors. A total 2005 samples of fecal swab isolated from a piglets in farm of Badung, Tabanan, Gianyar and Denpasar regency, district of Bali. Fecal swab samples were collected from feces and continued by isolation and identification Escherichia coli. This study showed that, the incidence of colibacillosis in piglets were 846 (42%) and the high risk factors occurrence of colibacillosis for young piglets between 0-2 weeks (62%)