Some studies have suggested that the use of sunscreens to prevent skin cancer may put the population at risk of vitamin D deficiency. We followed 24 sunscreen users and 19 controls over 2 years, including two summers, two winters and a basal period (winter). Vitamin D, parathormone and bone biological markers were evaluated each season. Mean levels of 25- hydroxyvitamin D rose in summer, with the increments being significantly higher for the second year in the control group. Levels decreased in winter in both groups, and were significantly lower in sunscreen users. We did not observe any significant change in parathormone, tartrate resistant phosphatase, total alkaline phosphatase, osteocalcin, urine hydroxyproline or urine calcium. Clinically prescribed sunscreen creams (sun protection factor 15) caused a minor decrease in 2 5-hydroxyvitamin D levels, which did not induce secondary hyperparathyroidism or an increment in bone biological markers.