Experimens were conduced to study the effects of Puberogen V. oil (Chorionic Gonadotrophin) on the growth of gonad and follicle in immature hens. The 105 days old hens were injected with Puberogen V. oil in dose of 10, 20, 30, 40 and 50IU. and the changes of their ovaries, oviducts and follicles were observed. The results indicate that: 1) Ovary weight was increased with the increase of the injected does and was the heaviest at 1023.8±7.71㎎. in 50IU. treatment group in comparison with control group (553.6±7.31g.) correlation between ovary weight and the injected does was highly positive, showing the significance with p$lt;0.01. 2) Oviduct weight was increased with the increase of the injected does and was 15.8±3.05 ㎎ in 50IU. treatment group in comparison with control group of 161.2±9.44㎎, showing positive correlation and the significance with P$lt;0.01. Oviduct length also went on increasing with the injected does and was 15.8±0.27㎝ in 50IU, treatment group as compared with control group of 10.24±0.23㎝, showing positive correlation and the significance with P$lt;0.01. 3) Follicle was not specialized in control group, remaining as the original cell. In treatment groups, follicle was specialized slightly in 10IU. treatment group with 1.8±0.20 pieces in comparison with control group showing no significance, and in the groups with more than 20Iv. it was increased gradually to 14.0±1.41 pieces in 50Iv. treatment group showing positive correlation and the significance with P$lt;0.01 among the averages. Diameter of follicle went on increasing as the injected does and was the largest at 4.0±0.1 ㎜. in 50IU. treatment group showing positive correlation and significance with P$lt;0.01 among the averages.