Abstract: The invention relates to a hydrocracking and hydrotreating process for hydrocracking feedstock oils such as vacuum gas oil to produce diesel and lighter distillate products. A first hydrogenation process is carried out in a main reactor with the feedstock and hydrogen flowing cocurrently down through a top section containing a layered system of hydrotreating and hydrocracking catalyst. The feedstock is substantially desulfurized and denitrified, the aromatics are at least partially saturated and cracked products are formed. The vapor and liquid are separated in a disengaging zone below the top section and the liquid flows down through a bottom section also containing a layered catalyst system countercurrent to make-up hydrogen flowing up. The vapor removed from the disengaging zone and the liquid bottoms are then further processed in a post treatment catalytic distillation reactor having an upper catalytic distillation section and a lower stripping section which may also contain a catalyst.