One of the greatest problems in environment is accumulating of non-biodegradable polymers. Due to the hardness of these polymers, the biodegradation process is very slow. Several microorganisms have the potential for production of biodegradable polymers such as PHAs. Polyhydroxyalkanoates (PHAs) found in the cytoplasm of the bacterial cell as sources of carbon and energy. In the current study, 20 microbial strains related to bacteria were isolated from different areas in Makkah. Collected isolates were screened to examine their ability in production of PHB. Bacillus sp (F15) were selected based on their high production of PHB. Bacillus was maintained on (Luria Bertani broth medium) which showed PHB maximum production after 48 hours at 30 °C and the optimum pH is 7 under shaking conditions. Carbon and nitrogen sources were used to study their affect on production of PHB. Glucose is the best carbon source for PHB production, while (NH₄)₂SO₄ is the best nitrogen source. Strain (F15) was characterized by morphological, biochemical test and identified as Bacillus sp.