With the emergence of urban transformation concept in 1980s, the concept of eligibility has also started to be discussed as a new term in Turkey. However, the absence of a sustainable urban transformation law which defines the criteria of eligibility of stakeholders has undoubtedly brought about violations and disagreements between stakeholders. Especially the uncertified gecekondu possessors who are not determined as eligible stakeholders have been subjected to forced and arbitrary evictions. This study aims to clarify the problem of eligibility of uncertified gecekondu possessors in urban transformation and attempts to determine the criteria for the eligibility of this particular group. It argues that since the claims of uncertified gecekondu possessors like right to adequate housing, labor and possession have moral characters which do not depend upon legal acts, they can not be criteria of eligibility. The legal property ownership must be the criteria of eligibility in urban transformation practices in the law. On the other hand, this study urges that no matter living in a legal or illegal housing, the vulnerable families who lack of basic economic security and living in the project area must be determined as eligible stakeholders. In the first part of this master study, the problem of eligibility was discussed from theoretical perspective. In the second part, this problem was discussed in the case of Dikmen Valley 4th and 5th phases Urban Transformation Project. The knowledge obtained from the case can be useful for the local governments to develop sustainable policies on this particular problem.