The author Mike Davis has labelled our entire globe as a planet of slums. This hesis aims to provide some insights to the research field of slum rehabilitation, and thus contribution to efforts to make our globe slum free. The United Nations states that security of tenure is one of the essential preconditions for improvements in slums. The statement comes with support from academic research, which highlights the relation between secure tenure and a slums physical quality. Out of these messages two hypotheses are formulated and tested throughout the thesis; one theoretical, the other empirical. The theoretical section holds that tenure should be studied according to property rights and tenure status, that interventions for slum rehabilitation should support the dwellers efforts of incremental development, that tenure is granted in both the informal and formal land market, and that there are several causalities between secure tenure and the quality of housing and infrastructure. The case study examines 208 informal settlements in terms of their living conditions in the city of Pune, India. The thesis draws on empirical data in the form of a citywide slum survey that has been made available by the non-governmental organisations, Maharashtra Action League and CHF International, both of which operate in Pune. The empirical section reveals that secure tenure does not influence housing quality at all, that secure tenure just slightly influences available infrastructure in a settlement, and that urban planners are able to support a sustainable and incremental rehabilitation of slums by focusing on tenure security.