Urban space is among those scientific concepts that have gain widespread currency in sociology, anthropology, architecture, and urban development and that has different definitions and application in these fields. In one classification of its dimensions, criteria and principles, urban space can have four dimensions of operational, formal, conceptual, and social. With reference to its nature and content, leisure time, too, is one the most important of social constructs that influences all aspects of social life. The effects of this social construct can be studied, not only on the micro level of the individual, but on the macro level of economic, social, political, and cultural dimensions of life. This paper aims to study the effects of urban social space on the leisure time activities of the youth in Shiraz, with an emphasis on social activities. For this purpose, 400 individuals aged 18-25 Shirazi youth were selected, using a multi-stage cluster sampling technique. Research method was quantitative and the technique of data collection was survey (questionnaire and interview). The results showed that leisure time activities was positively associated with socio-economic status (R= 0.474), urban social space (R= 0.358), social participation (R= 0.231), value acceptance (R= 0.208), and education (R= 0.088) and that these relationships were statistically significant. The coefficient of determination of all five independent variables was 0.42.