The beaded lizard (Heloderma horridum) is listed as a threatened species in Mexico. Scientific research has been limited to two sites within its range (Chamela and Valle Motagua) outside of these two regions there have not been adequate surveys to define range limits or measure environmental correlates for defining suitable habitat. We constructed an ensemble model (EM) for the distribution of suitable habitat for H. horridum in both Mexico and Guatemala and then used that model to identify potential areas to focus conservation. We used nine presence-only modeling methods, and selected three to generate our EM. We used the EM to evaluate the efficacy of the existing Protected Natural Areas (PNAs) in Mexico and Guatemala for H. horridum. Also we used the best individual predictive model (Maxent) to obtain the most important factors for H. horridum presence and used them to analyse the habitat use; finally we used our predictive model to calculate niche breath for the species. The estimated potential distribution of H. horridum is 370,474km 2; within this area we identified nine zones based on continuity and natural barriers. About 1.5% of the species distribution is under protection in the PNAs. The five most important factors for the presence of this species explained 78.2% of the generated model and are related to seasonality and soil cover, and these are used selectively. This species is closely associated with tropical deciduous forests, one of the most threatened ecosystems worldwide and is inadequately protected in both Mexico and Guatemala. Our results clearly show the necessity of a protection plan for this species. � 2012 Elsevier GmbH.