The textile industry is one of the biggest industries in the world and its wastewater is one of the most important threats to the environment and human health. In this study, the ability of Haloarcula sp. IRU1 to produce poly(3-hydroxybutyrate) (PHB) was investigated using a basal salts medium. Different factors like textile wastewater, yeast extract, and KH₂PO₄ (as carbon, nitrogen, and phosphorus sources, respectively) were optimized to achieve maximum synthesis of PHB by Haloarcula sp. IRU1. Under the optimal conditions of textile wastewater 30% (v/v), yeast extract 0.2% (w/v) and KH₂PO₄ 0.008% (w/v), the highest PHB synthesis (1.54 g/L) occurred in a shake-flask culture. The results provided evidence that Haloarcula sp. IRU1 could be a potential microorganism for production of PHB from textile wastewater in different conditions.