Technical Abstract: Advisory groups that make recommendations for mineral intakes continue to identify accurate determinations of sweat mineral losses during physical activity as a critical void in their deliberations. Although estimates of sweat mineral concentrations are available, they are highly variable. Practical assessments use various sites on the body to collect sweat because of the difficulty to collect whole-body sweat during exercise. Iron and zinc concentrations in the sweat obtained from the abdomen and chest were more than twice as large as compared to the arm and back. However, use of regional sites overestimated whole-body loss of calcium more than 300%. Similarly, exercising in a cool compared to a hot environment resulted in decreased iron and zinc concentrations at the arm. Iron retention was significantly reduced in men consuming high (~35 mg) and usual (~18 mg/d) iron intakes and exercising in the heat when sweat losses of iron were included in the balance calculation. Also, inclusion of estimates of zinc loss in sweat of physically active men decreased zinc retention. A few studies reported that measured sweat losses of minerals during exercise were appreciable, and accounted for 10, 9 and 3% of recommended daily intakes of calcium and zinc, and iron, respectively. Further work using valid measurements of sweat losses of minerals is need. This information will be useful to dietetic and nutrition professionals who counsel physically active people.