ABSTRACT This study aimed to determine the effects of the variation in body weight (BW) in pure lines even after selection on the BW and feed conversion ratio (FCR) of offsprings in broiler pure-lines. The males of the dam (A1) and sire (B1) line were grouped according to their BW after selection at the 6th and 12 th weeks of age. In the sire lines, the heaviest males at six weeks of age were selected (300), and the selected males were divided into three groups in terms of BW as average (B11: 100 males), high (B12: 100 males), and the highest (B13: 100 males). In the dam lines, the selected males were divided into three groups as an average (A11: 100 males), low (A12: 100 males), and high BW (A13: 100 males). In the dam line, offsprings of males with average and high BW had the highest BW at 42 days of age compared to the low BW group (p<0.05). However, there was no statistically significant difference in BW between the BW groups in the offsprings of the sire line. Offsprings of dam line males with average and higher than average BW had better FCR values. However, there was no significant change in FCR between the offsprings of the sire line BW groups. As a result, it is thought that by preserving the variation at a certain level in future generations, a significant improvement can be achieved in the BW and FCR by selecting heavier males.