Despite the abundance of descriptive studies on the urban development plans of Ankara, analytical studies on specific features of these plans, especially on implementation and modification processes are scarce. This study examines the green space structure brought in Jansen&rsquo / s 1932 development plan of Ankara, the way it was implemented and the modifications that a component of this structure was subject to. The 1932 Jansen plan is a holistic and comprehensive plan that contained a conceptual green space structure, integrated with other public uses and social facilities. An in depth evaluation of Jansen&rsquo / s 1928 and 1932 plans is made and a typology of the components of the green space structure is formed. It is found that the plan principles and the components of the green space structure of Jansen&rsquo / s plan for Ankara are perfectly congruent with German planning approach and principles of the time. From the analysis of the plan modifications of the G&uuml / ven Park- Tandogan Greenway a typology of modifications is developed. It is argued that the 1933 and 1957 development laws and regulations lacked definitions for realizing and sustaining the green space types proposed by Jansen, which consequently lead to their modifications. In reality the land ownership status, &ldquo / h&acirc / l&icirc / arazi&rdquo / , under which the greenways of Jansen plan were placed, illustrates the difficulty of translating these spatial categories into the Turkish legislative framework. In this respect, this study is an attempt to provide a contribution to the study of green spaces in relation with the implementation of development plans.