With more than 132 million of patients estimated in 2050, Alzheimer's disease is a worldwide public health problem with no current treatment. Its diagnosis especially consists into realizing paper assessments exploring the different fields of cognition. Virtual reality has become an essential tool in informatic and in medical practice. Due to their lack of immersion, paper tests are not ecological and so virtual reality appears to be more ecological. We aimed to create virtual cognitive tasks in an immersive environment. These tasks were inspired from usual tests such à Mini Mental Examination Status or Montréal Cognitive Assessment. Thirteen scenes with different models were edited and uploaded in the Oculus Quest. Multiple cognitive functions were tested such as orientation, attention, memory or praxis. The system let an easy and autonomous utilization with an avatar. Our issue is now to test it on a healthy population and in AD patients to validate its validity and reliability.