Present study was carried out to find out an optimum interval for artificial insemination in aged and poor laying hens, Brown colored, hundred and twenty commercial laying hens at about 530 days old and 20 S. C. W. Leghorn males at 580 days old were adopted Egg production rate during the experiment was 61.6% and number of eggs examined was 2,283. The intervals for the insemination were 2, 4 and 6 days for experimental groups T-1, T-2 and T-3, respectively. Eggs were collected on every 6th day and examined for fertility by candling after 5 days of incubation. Average fertility rates for T-1, T-2 and T-3 groups appeared 87.5, 81.1, and 65.1%, respectively. The fertility of T-3 group was significantly lower than those of T-1 and T-2 groups(P＜0.05). The highest fertility rate was obtained on the second day after the insemination for all groups, i. e. 90.7, 84.0 and 71.7% for T-1, T-2 and T-3, respectively. Thereafter, a tendency of gradual decline in fertility was observed. This study suggests that the optimum interval for artificial insemination in aged hens is 2 days. The fertility tended to be improved by repeated injection. For the 2-day interval group, the highest rate (98.2%) was obtained on the 6th insemination.