As respiratory system diseases in childhood are very common, lung function tests are in demand. The least complicated measurement of lung function is the recording of flow and volume plotted as a loop during tidal breathing. Recently, tidal flow-volume loop (TFVL) analysis has been extensively used as a valuable, simple, and relatively noninvasive lung function technique in infants and children. Lung function measurement by tidal breathing is a method that can be performed at any age, with minimal patient cooperation, or even when the patient is sedated. TFVL analysis has not been found to negatively alter respiration even in acutely ill patients. This article reviews technical and practical issues related to TFVL analysis. Influence of measurement conditions, as well as comparison with other commonly used lung function tests are also discussed. The different areas of TFVL applicability in diagnosis, disease management, and research are shown.