 In the 2007–2008 Cyclo-cross season, Boom won a World Cup event in Pijnacker, a Gazet van Antwerpen event in Loenhout and then became Dutch Elite National cyclo-cross champion for the second time.After that, he also won the World Cup races in Liévin and Hoogerheide.He went into the world championships in Treviso 2008 as big favourite and did not fail, he won the race and became the second rider after Radomír Šimůnek to win the world title in all categories (Junior, Espoir and Elite).