he paper discusses sustainability and vulnerability issues related to critical underground infrastructure (CUI). CUI is defined on the basis of its provision of vital services for a community. Most CUI can be found in urban areas. This analysis is based on understanding the natural characteristics of underground space and the benefits and difficulties of its utilization. Sustainability analysis considers how CUI is sustainable itself and what its impact on the environment is. Similarly, vulnerability analysis breaks down external and internal threats to CUI, and CUI impact on vulnerability of the physical and functional environment. The multiple-criteria decisionmaking analytic hierarchy process is used for aggregation impacts and integral assessment of CUI. In conclusion, the importance of CUI planning is highlighted.