The process development by IFP Energies nouvelles (IFPEN)/ENI/Axens of a Fischer-Tropsch process is described. This development is based on upstream process studies to choose the process scheme, reactor technology and operating conditions, and downstream to summarize all development work in a process guide. A large amount of work was devoted to the catalyst performances on one hand and the scale-up of the slurry bubble reactor with dedicated complementary tools on the other hand. Finally, an original approach was implemented to validate both the process and catalyst on an industrial scale by combining a 20 bpd unit in ENI’s Sannazzaro refinery, with cold mock-ups equivalent to 20 and 1 000 bpd at IFPEN and a special “Large Validation Tool” (LVT) which reproduces the combined effect of chemical reaction condition stress and mechanical stress equivalent to a 15 000 bpd industrial unit. Dedicated analytical techniques and a dedicated model were developed to simulate the whole process (reactor and separation train), integrating a high level of complexity and phenomena coupling to scale-up the process in a robust reliable base on an industrial scale.