Diane at Te Deum laudamus has done a thorough job of researching and — in my opinion — debunking the “Marian apparitions” at Medjugorje.
I don’t see the need to add much commentary. I will simply say that I do not believe that a spirituality based largely on any apparition (and belief in these is left to the discretion of the individual Catholic) is healthy; it is far more sound to ground one’s prayer life and apostolate on the certain teachings of the Church and the examples of Her saints. And, in the particular case of Medjugorie, there is enough weighing against the legitimacy of the “apparitions” to make devotion to it especially unsound — rebellion against the local bishop, the unedifying lifestyle of the “seers,” faulty predictions, endless “visions,” etc. If one has a devotion to Our Lady — and I do — why not supplement it with study on Fatima, Lourdes, and other Church-approved apparitions, instead of stubbornly grasping this dubious one?!
Holy Mary, Mother of God, pray for us sinners!