Body mineral composition was determined in 81 pigs killed at birth, weaning (28 d), and at approximately 15-kg intervals to 145 kg of BW. Total body components, including internal tissue, whole blood, and hair, were wet-ashed and analyzed for their mineral contents with the inductive coupled plasma method, except for Se, which was determined by fluorometric analysis. The results demonstrated that the body protein:ash ratio increased from birth to 20 kg BW, remained constant to 125 kg, but then declined to 145 kg BW (P < .01). The K:Na ratio increased from birth to 105 kg BW and then reached a plateau (P < .01). The Ca:P ratio decreased from birth to 20 kg then remained relatively constant to 90 kg BW, whereupon it increased (P < .01). These ratios reflected the rate of development of muscle and bone tissue and the higher soft tissue requirement for P and K during early growth. When expressed on a fat-free tissue basis, body Na was higher than K at birth, but thereafter body K increased linearly (P < .01) and Na content declined (P < .01). When Mg, Mn, Mo, and Cr were expressed on a fat-free empty body weight basis, each increased from birth but they maintained the same relative concentrations from 20 to 145 kg BW (P < .01). Body Fe increased from birth to 20 kg BW but then gradually declined to 145 kg BW (P < .01), whereas Zn increased to 145 kg BW (P < .01). Selenium increased from birth to weaning and again after 105 kg BW (P < .01). The amount of Co in the fat-free empty body increased linearly (P < .01) with increasing pig weight, and body Cu decreased to 75 kg BW and then reached a plateau (P < .01). The nonessential elements Al, Sr, and Sn increased dramatically from birth to weaning with a low rate of increase from 8.5 to 145 kg BW (P < .01), but Sn decreased after weaning (P < .01). The nonessential elements generally had a more variable concentration than the dietary essential trace minerals. There was a quantitative increase (P < .01) in all macro- and microelements from birth to 145 kg BW.