Protein refolding is the phenomena by which the inactive protein is translated into its native form generally by folding in dilution buffer. The dilution buffer often needs to be clarified before subjecting to further purification processes. The key challenge in the pre-filtration step is to minimize the product loss, obtain desirable filtrate quality to enhance the efficiency of subsequent purification processes. Cellulose based depth filters are widely used in biopharmaceutical industry for this application. Zeta plusÂ EXT SP series - dual zone depth filter grades were screened to ascertain the clarification performance. The results showed that Zeta plus EXT 60SP02Acould deliver optimumthroughput and flux, and desirable filtrate quality required to protect the downstream equipments such as chromatographic columns and thereby bringing down the overall filtration costs and downtime in the scale-up.