Two genetic lines of barrows and gilts with different lean growth rates were used to determine the BW and chemical composition growth from 23 to 125 kg of BW. The experiment was a 2 × 2 × 5 factorial arrangement of treatments in a completely randomized design conducted in 2 replicates. At slaughter, tissues were collected and weighed. All components were ground and frozen until analyzed for water, protein, lipid, and ash. It was found that Overall, barrows had 21.3% greater lipid deposition (279 vs. 230 ± 78.2 g/d) than gilts. However, Barrows and gilts had similar predicted daily moisture, protein, and ash accretion rates.