PurposeConjunctival and cutaneaous melanoma partially share similar genetic alterations. β‐catenin is a dual‐function protein that acts not only as a structural component of adherens junctions but also as an effector molecule involved in the Wnt pathway. In skin melanoma, in vitro activation of the Wnt pathway led to nuclear localization of β‐catenin and increased invasiveness. We investigated the expression and activation of β‐catenin in benign and malignant conjunctival melanocytic proliferations.Methodsβ‐catenin expression was assessed by immunohistochemistry in 43 conjunctival naevi, 48 PAM (including 23 PAM with atypia) and 44 conjunctival melanomas as well as in 4 conjunctival melanoma cell lines at various stages of confluence. Statistical analysis was performed with JUMP 8.0 software.ResultsIn the naevi, membranous expression of β‐Catenin was found in all the cases and nuclear expression in 14% of the cases. In the PAM, membranous expression of β‐catenin was identified in all the cases without nuclear expression. Membranous expression of β‐catenin in melanoma was found in 94% of the cases and nuclear expression in 15.9% of the cases. There were no significant differences in the nuclear expression of β‐catenin between conjunctival nevi and melanoma. In the melanoma group, there was a significant correlation between nuclear expression of β‐catenin and depth of invasion. In the 4 conjunctival melanoma cells lines, no significant nuclear expression of β‐catenin was identified at various stages of confluence.Conclusionsβ‐catenin activation and nuclear localization does not appear to be a major mechanism occurring in conjunctival melanoma. It is however possible that β‐catenin activation might occur at a late stage in tumor development.