While Juan Diego is known for his role in the Marian apparitions, there is no evidence or tradition that he performed any miracles himself. The miracles attributed to him are related to the events surrounding the apparitions, including:
1. The Tilma of Juan Diego: The most famous miracle associated with Juan Diego is the image of the Virgin Mary that was miraculously imprinted on his tilma, or cloak, during one of the apparitions. The tilma, which was made of poor-quality cactus fiber and should have disintegrated over time, has remained intact and shows no signs of deterioration or fading.
2. Healing of Juan Bernardino: Juan Diego's uncle, Juan Bernardino, was seriously ill and on the verge of death when Juan Diego encountered the Virgin Mary during the third apparition. The Virgin instructed him to take some flowers that she had shown him to Bernardino, and when Bernardino touched the flowers, he was instantly healed.
These events, which occurred in the context of Juan Diego's Marian apparitions, are considered miraculous and have played a significant role in the devotion to the Virgin of Guadalupe and the canonization of Juan Diego.