Established in 1982, the Aruba Island rattlesnake Crotalus unicolor Species Survival Plan (SSP) is the longest continual functioning snake conservation effort of the Association of Zoos & Aquariums (AZA). The captive population has been maintained as an assurance population for the most threatened snake on Aruba. Over the last 26 years, 27 potential founders were imported for assimilation into the SSP to maintain genetic diversity. By 2014, the gene diversity in the captive population was over 94%. In 1986, the SSP began working in partner- ship with Arubans to aid the conservation of the rattle- snake and its ecosystem on the Island. This in situ programme has included ecological research, training, management recommendations, capacity building, workshops, public relations and education. These efforts have been integrated into a holistic long-term project that has resulted in many significant conservation suc- cesses. The extensive efforts made by the AZA and SSP to ensure the continued survival of C. unicolor are a model for zoo-based conservation efforts involving reptiles.