OBJECTIVE: To assay drugs that modify pigmentation (ie, agents that either enhance or decrease pigmentation) in a predictive in vitro model, as such drugs have been previously studied in vivo on human and animal skin. DESIGN: An epidermis was reconstructed with human keratinocytes and melanocytes. Epidermal reconstructs with melanocytes were made according to a variant of the model of Prunieras and colleagues. Reagents that alter melanogenesis such as isobutyl methylxanthine, 1-oleoyl-2-acetyl-sn-glycerol, kojic acid, and mequinol were introduced in the culture medium or used topically after 8 days of culture at the air-liquid interface. MAIN OUTCOME MEASURES: Macroscopic, colorimetric, histological (Fontana-Masson stain and dopa reaction), and biochemical studies were performed. RESULTS: The effect of pigment modifiers was demonstrated ex vivo as expected from in vivo data on skin color, numbers of melanocytes, melanosome transfer, and melanin content. CONCLUSION: These results will permit other investigators to use this model to assess the efficacy of novel molecules that alter pigmentation.