A review of flood impact assessment approaches for underground infrastructures in urban areas: A focus on transport systems.Flooding events can produce significant disturbances in underground transport systems within urban areas and lead to economic and socioenvironmental wellknown consequences, which can be worsened by variations in the occurrence of weather and climate extremes. A better comprehension of these impacts and their conditions is consequently needed. Hence, this paper presents a state-of-the-art literature review on flood impact assessment in metro systems, analysing their purposes and their shortcomings. This document shows the adaptation measures dealing with specific classes of pluvial flood damages, besides identifying prospective paths towards the application of suitable actions facing actual and projected hazards in metro systems worldwide.