Azole resistance is emerging in Aspergillus fumigatus isolates. The exact mechanism of evolution of azole resistance has not been fully elucidated yet but increasing evidence indicates a role for azole fungicide used in agriculture. Patients confronted with an invasive fungal infection from an azole-resistant A. fumigatus isolate will fail azole treatment. Azole resistance in A. fumigatus isolates impacts the management of invasive aspergillosis (IA) since the azoles are the primary agents used for prophylaxis and treatment. Because A. fumigatus will always be present in our environment and also in the close vicinity of patients at risk for IA, there is an urgent need to understand the evolution of the increasing azole resistance in A. fumigatus. Thereby, induction of azole resistance or its spread can possibly be prevented to allow future treatment of A. fumigatus IA.