ABSTRAK. Ayam Gaok merupakan salah satu rumpun ayam lokal yang memiliki potensi besar dikembangkan. Balai Penelitian Ternak (Balitnak) telah melakukan program seleksi pada ayam Gaok untuk menghasilkan bibit ayam lokal pedaging yang dipanen umur 10 minggu dan dapat dijadikan galur jantan (male line) yang akan disilangkan dengan ayam KUB yang merupakan galur betina (female line). Tujuan dari penelitian ini untuk mengetahui pertumbuhan bobot badan dan karakteristik semen ayam Gaok generasi ke-6 yang dipelihara di Balitnak. Sebanyak 211 ekor anak ayam Gaok umur satu hari dari generasi ke-6 dipelihara pada kandang koloni pada masa starter dan grower. Ayam dewasa dipelihara pada kandang individu. Pakan dan air minum diberikan ad libitum. Bobot badan ayam jantan dan betina pada umur 10 minggu masing-masing 1.075,26 ± 156,55 g (KK= 14,56 %) dan 868,25 ± 109,34 g (KK= 12,59 %). Rerata bobot badan jantan dan betina sudah mulai berbeda nyata (P0,05) pada saat ayam berumur lima minggu. Konsumsi dan konversi pakan sampai umur 10 minggu yakni masing-masing 2.801,61 g dan 2,99. Bobot badan ayam jantan dan betina pada umur 20 minggu masing-masing 2.354,01 ± 280,06 (KK= 11,90%) dan 1.646,5 ± 205,97 g (KK= 12,51%). Volume semen, konsentrasi, motilitas dan persentase sperma hidup ayam Gaok jantan pada umur delapan bulan masing-masing sebesar 0,4 ml, 3.927 × 106, 57,22 dan 62,5%. Bobot badan ayam Gaok umur 10 minggu menunjukkan hasil baik dengan variasi yang cukup seragam. Kuantitas dan kualitas semen ayam Gaok tergolong normal. (Analysis of body weight and semen characteristic of 6th generation selected gaok chicken) ABSTRACT. Gaok chicken is one of local breed chicken which potentially to be developed. Indonesian Research Institute for Animal Production (IRIAP) have been executed selection program on Gaok chicken to obtain meat type local chicken which is harvested on 10 weeks old age and can be made as male line to be crossed with KUB chicken which is the female line. The objective of this study was to observe growth of body weight and characteristics of semen of Gaok chicken 6th generation which are raised in IRIAP. A number of 211 DOC Gaok chicken 6th generation were raised in colony cage in starter and grower periods. Mature chickens were kept in individual cages. Feed and water were given ad libitum. Body weight male and female at 10 weeks were 1,075.26 ±156.55 g (CV=14,56 %) and 868.25 ± 109.34 g (CV=12,59 %) respectively. Body weight on male and female were started significantly differ from five weeks (P0.05). Feed consumption and conversion for 10 weeks were 2,901.61 g and 2.99, respectively. Body weight male and female at 20 weeks were 2,354.01 ± 280.06 g (CV=11,90 %) and 1,646.5 ± 205.97 g (CV=12,51 %) respectively. Semen volume, concentration, motility and proportion of live sperm of male Gaok chicken were 0.4 ml, 3,927 × 106, 57,22 % and 62.5 %, respectively. 10th week body weight of Gaok chicken showed good results with uniform variation. Quantity and quality of Gaok chicken semen belonged to be normal.