We conducted a systematic review of the association between melanocytic nevi (MN) in childhood and sunscreen use. A bibliographic search was conducted between November 2008 and January 2009 using the following key words on MEDLINE and EMBASE: child*, in combination with naevi, nevi, naevus, nevus and sunscreen, sun protection. We also used Medical Subject Headings [sunscreening agents], or [radiation protection] with [nevus, pigmented]. A first screening was done on title and abstract reading. Randomized trials and cohort and cross-sectional studies analyzing the relationship between the use of sunscreen and MN in children were selected. Three reviewers abstracted data from each article. The three sets of results were compared for concordance and rereviewed if necessary. Fifteen articles were included (20,743 children). The studies were not consistent in terms of the ages of the children, MN count methods, or sunscreen use assessment. Owing to this heterogeneity, we were unable to pool the studies and conduct a meta-analysis. Twelve studies did not report that the use of sunscreen had a protective effect against MN development. Three studies reported a lower MN count when sunscreen was applied. This systematic review underlines the methodologic differences between studies. Eight of 15 studies reported a positive association between sunscreen application and MN count. Differences in MN counts, overexposure to sun, and inadequate sunscreen application on fair-skinned children could explain the disparity in the results. There is still no evidence of a protective effect of sunscreen against MN development in children.