Under the pressure from investors, Slovakia has experienced significant urban sprawl into the countryside in the last three decades. This development resulted in the loss of agricultural land, despite the fact that towns and cities in the built-up area have great potential in the vacant land lots. It is crucial to identify the lost spaces and incorporate them in the regeneration of urban structure and green infrastructure of Slovak towns and cities. The paper presents the results of the case study of lost spaces in Slovak towns that aimed to confirm the hypotheses: