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Thermoalkalistable lipases enzymes occupy a very important group used for bioremediation of environmental pollutants, act as biocatalysts and many other industrial application. One of the major industrial microorganism is the Bacillus sp. which are abundance in the desert localities. The aim of this research was to isolate, characterize of lipase producing bacteria from Khormah slaughter house wastes (SHW), Taif, Makkh, KSA, thermoalkalstable lipase production and its purification. SHW was found to be the most successful natural source for thermoalkalstable lipase production. Twenty eight lipase producing bacterial isolates were isolated. One strain was selected as a best thermoalkalistable lipase producer identified by morphological, physiological and biochemical characteristics as Bacillus stearothermophilus KGSHW-1. The identification was confirmed by molecular biology technique. Different factors such as temperature, pH, incubation period, nutritional requirements, substrate concentration, inoculum size, vitamin requirements, effect of metallic ions, effect of incubation condition and bottle capacity were studied for improving thermoalkalstable lipase production. An optimum conditions for production of thermoalkalstable lipase by B. stearothermophilus KGKSA-1 was achieved at 60 degrees C, after 24 h. of fermentation at pH 10. Beef extract, vitamin B6 were the best carbon source and vitamin source, while potassium nitrate served as a source for nitrogen. Tryptophan was served as best amino acids, substrate concentration 75 (%,w/v) inoculated by 1 ml (7 x 10(10) CFU.ml(-1)) under shaking conditions in 2.5% of 250 ml capacity. BaCl2 was induced the enzyme production. This enzyme was purified using acetone concentration 60% precipitation and gel filtration column using Sephadex G200 and 100 respectively. The purification fold steps for precipitation by acetone, dialysis against sucrose, Sephadex G200 and Sephadex G100 were found 2.086, 1.43,14.9 and 39.8 respectively. Sodium dodecyl sulphate revealed that the monomeric lipase has 60 kDa of its monomeric lipase. These results show a great potential for the use of this produced enzyme in industry and other future studies. [Bayoumi, R.A., Atta, H.M. and El-Sehrawy, M.H. Bioremediation of Khormah Slaughter House Wastes by Production of Thermoalkalistable Lipase for Application in Leather Industries. Life Sci J 2012;9(4):1324-1335] (ISSN:1097-8135). http://www.lifesciencesite.com. 201