Career
He also participated at the 1999 European Junior Championships and the 2000 Open Water World Championships. In 2001 he was confronted with leukemia and his career was likely to be over. After surviving cancer he made his comeback in 2003.
He became seventh over 10 and 25 kilometres at the 2004 World Open Water Championships and added a Dutch title at the 800 m freestyle (lc) and 25 km open water.
Later in 2004 he swam across the IJsselmeer in 4:20.58 hours, breaking the former record by almost 15 minutes to collect 50,000 Euros which he donated to cancer research. He finished in fifth position at the World Open Water Championships over 10 km and sixth over 25 km.
Van der Weijden had his own website named "Maarten van der Weijden zwemt tegen kanker" (Maarten van der Weijden swims against cancer) where he informed his fans about his life and his career. He also collected more money for cancer research.
At the end of the World Cup calendar he finished in second position overall and during the 2007 World Championships over 10 km he finished seventh.
This result qualified him for the 10 km open water marathon race at the 2008 Summer Olympics in Beijing. He announced the end of his professional swimming career during his acceptance speech as Dutch Sportsman of the year in 2008.