Ultraviolet radiation is the major environmental insult to the skin and stimulates the synthesis of melanin in melanocytes, which then distribute it to the neighboring keratinocytes where it confers photo-protection. Skin color results from the paracrine interaction between these two cell types. Recent studies suggest that endocannabinoids are potential mediators in the skin. Here, we investigated whether cannabinoid drugs play a role in melanogenesis and if ultraviolet radiation modifies the cutaneous endocannabinoid system. We used human melanotic melanoma cell line (SK-mel-1) in monoculture or co-culture with human keratinocytes (HaCat). Endocannabinoid levels, cannabinoid receptors expression, and melanin content were evaluated under basal conditions and after ultraviolet-B irradiation (311 nm). We provide evidence that human melanoma cells (SK-mel-1) express CB(1) receptors, and when in co-culture with keratinocytes (HaCat), the selective CB(1) receptor agonist arachidonyl-2-chloroethylamide (ACEA 1 and 10 μM) inhibited (by 33.4 and 37.3%, respectively) basal melanogenesis. In addition, ultraviolet-B-induced melanogenesis in co-cultures was abolished by ACEA 10 μM. Both ACEA inhibitory effects were reversed by AM251 (1 μM), a selective CB(1) antagonist. Furthermore, ultraviolet-B radiation increased endocannabinoids levels only in keratinocytes, whereas CB(1) cannabinoid receptor expression was up-regulated only in melanoma cells. Our results collectively suggest that ultraviolet radiation activates paracrine CB(1)-mediated endocannabinoid signaling to negatively regulate melanin synthesis. The endocannabinoid system in the skin may be a possible target for future therapies in pigmentary disorders.