This work takes up the task to present and discuss in more detail certain aspects of Islamisation in the Ottoman Balkans that have been left unsatisfactorily studied up to now. Utilising petitions for conversion to Islam (kisve bahasi arzuhals) in combination with other supporting primary sources, it is meant to cast more light upon the actual mechanisms of conversion, patterns of motivation, as well as the possible factors that conditioned the process of Islamisation in the Ottoman Balkans during the late 17th and the first half of the 18th Centuries and to show that at least in the light of these documents Balkan Islamisation during the period in question was a gradual process influenced by a complex set of factors, whereby fiscal pressure and the quest for social advancement played a prominent role. Lastly, post-conversion socio-religious practices as well as the multifaceted attitude of the Ottoman state and Islamic legal tradition towards "new Muslims" will be discussed.