Two genotypes of pigs with different lean gain potentials (280 vs. 326 g FFL/d) with an equal distribution of gilts (n = 60) and barrows (n = 60) were used to evaluate body mineral composition during the period from 20 to 125 kg BW. Both genotypes were housed at a single site and fed common diets during the nursery period to adjust the animals to common environmental conditions. At 20 kg BW the pigs were moved to a complete confinement facility and split sex fed a corn-soybean mixture meeting or exceeding NRC (1998) amino acid and mineral requirements for each genotype for their lean gain potential. A total of six pigs for each treatment group were harvested initially and at approximately 25 kg intervals to 125 kg BW. Pigs were harvested as they reached their pre-allotted harvest weight. At each weight period pigs selected for harvest were measured for height, width and length. Longissimus muscle area (LMA) and back fat depth (BF) measurements were made using real-time ultrasound and carcass measurements. The experiment was a RCB design with a 2 x 2 x 5 factorial arrangement conducted in two replicates. The data were analyzed by the PROC MIXED procedure of SAS using the animal as the experimental unit contrasting genetic line, gender, and weight periods. During the grower-finisher period BF deposition increased linearly (P < 0.01) and LMA demonstrated a quadratic increase (P < 0.01). Pigs with a higher lean gain potential grew faster reaching the targeted body weights with larger LMA (P < 0.01) and lower BF (P < 0.01). The results demonstrated a linear growth in pig width of the shoulder, ham and loin at the 10^th rib (P < 0.01). Mineral elements associated with lean tissue (i.e., K, Cl, Mg, S, Se, and Zn) had greater contents in the high lean vs. low-lean genetic lines, and with gilts compared to barrows. There was no difference in mineral content between genetic line and gender at 20 kg BW, but differences between genetic lines began to widen in an increasing manner from 45 kg to 125 kg BW. When minerals were expressed on a quantity per kg BW basis, no differer.