Abstract: In order to determine the threonine requirement of laying Japanese quails, one experiment was conducted using laying performance as parameters. In the study, a total of 40 female Japanese quails at 8 weeks of age were used. The quails were divided into four groups randomly. Experimental treatments consisted of four concentrations of total threonine using diets that ranged from 0.74-1.04% in progressive increments of 0.10%. Feed and water were supplied ad libitum and light was provided 16 h (from 8.00-24.00) each day. Laying performance was determined daily by measuring feed intake, feed conversion efficiency (feed intake/egg weight), egg production (number and weight). The experimental period lasted 9 weeks. Increasing threonine level in the diets increased feed conversion efficiency, total egg production (g/bird/63 days), egg weight (g/bird/day) and number of eggs (bird/63 days). However, there were no significant differences among the groups (p>0.05). About 1.04% threonine level in diet increased egg production 9.79% and number of eggs 9.30% compared with the basal diet (0.74% threonine). The results suggest that the current NRC recommendation of 0.74% threonine for laying quails is not adequate to support comparable laying performance.