Refiners are challenged to meet increasingly stringent fuel specifications even as the slate of available feedstocks becomes more difficult to process. Significant upgrades to existing facilities are often difficult to justify in an era of heavy capital restraint. Refiners must meet specific targets for long-term return on capital and product quality from middle and heavy distillate feedstocks for any investment to be attractive. IsoTherming® Hydroprocessing Technology provides a solution to the challenges refiners face to reduce sulfur in finished products to ultra-low levels while minimizing operating costs with competitive capital expenditures. This presentation highlights the principles of the technology and demonstrates the versatility and robustness of a process that has been successfully implemented commercially in grassroots and revamp applications to improve margins and ensure a safe and sustainable operating environment. This presentation will focus on revamp applications, in which the efficient design of the process provides refiners a means of debottlenecking and improving performance with minimal modification and no additional recycle gas compressor capacity. Revamps using IsoTherming® technology can result in significant capital savings in comparison to a conventional trickle bed revamp, with considerably more operational flexibility.