The SCK•CEN tritium laboratories were commissioned in 1975 for a maximum tritium inventory of 37 TBq. With an aim to improve the infrastructure, the capabilities and safety, SCK•CEN's general management decided to refurbish the laboratories. A new ventilation system, including a stack and gloveboxes equipped with a detritiation installation, will allow a higher tritium inventory limit of 0.37 PBq. This paper discusses the ongoing refurbishment of the two neighboring tritium laboratories. Currently one laboratory has been denuclearized whilst the other is still in operation. Nevertheless a number of conclusions can already be drawn. We succeeded in denuclearizing most of the equipment and infrastructure without personnel receiving measurable tritium doses. If the free released metals had been disposed off at a nuclear melting facility, 22% of the costs could have been saved, however free release is more socially acceptable.