The world of pre-existence has always been one of the most controversial Quranic and Islamic issues; and theologians, hilosophers and mystics have always argued about it. The holy Quran and the Islamic Hadiths (traditions) indicate that every human being has had a real individual existence in the world of pre-existence (in the first phase in a form of soul alone, and in the next one with a certain body called " particulate body") before he is born. Some of the Muslim thinkers have not accepted this interpretation of the Quran and Islamic traditions and have criticized it. This paper deals with some of the most important criticisms leveled at the world of pre-existence and their responses.