This chapter deals with product enrichment and the two unit operations are chromatography and distillation. Chromatography is a downstream processing technique, which can be used for concentrating or polishing the desired product. Hence, it can be used in the intermediate or final stages of the flow sheet. It is well suited for temperature sensitive materials including proteins, enzymes, peptide, etc. Distillation is well suited for recovering pure products, which are not temperature sensitive. The other separation process discussed in the Chapter 5 (such as, precipitation, ultrafiltration, dialysis, etc.) can also be used for final purification depending upon the requirements.