Analyses for 8 trace metals were made on hair samples of 126 male and 55 female subjects aged 1 to 102 years, most of whom patronized a barber shop. Marked variations were found. Samples of female hair had significantly more magnesium, copper and cobalt than did male hair. Young female hair had more copper, lead and cadmium than did hair from older women. Natural colored hair of females contained more magnesium, copper, lead, nickel and zinc than did natural colored hair of males. Grey hair of women had more magnesium and less cadmium and lead than that of men. In males there was more magnesium and less cadmium in black hair than in hair of other colors, less zinc in blond than in black or red, more lead in brown than in black or red and more nickel in red than in brown hair. In females there was less zinc in blond than in brown or red and less magnesium in brown than in red hair. Concentrations of the essential elements magnesium, zinc, copper, cobalt and chromium in hair did not decline with age in men, and were maintained in women after age 40. Nickel, cadmium and lead did not accumulate with age. It is doubtful that concentrations of these trace metals in hair reflect tissue stores under normal conditions.