Various configurations were studied to hydroprocess high-temperature Fischer-Tropsch (HTFT) vacuum gas oils to diesel fuel in compliance with EN590/Euro 4 fuel specifications. Conventional hydroprocessing generates a distillate not conforming to the fuel specifications; however, addition of an isomerization function and extra hydrotreating capacity markedly improved density and cold-flow properties. Hydrocracking the heavy part of the HTFT vacuum gas oil proved to be a viable alternative to generate a HTFT diesel with higher density and good cold-flow properties. Complementary blending studies confirmed that Euro 4 diesel fuel specifications are achievable by blending isomerized hydrotreated HTFT light distillate with HTFT heavy distillates and coal-pyrolysis-derived distillate fractions.