The lungs are complex 3D structuresstudied in the clinic and the laboratory using histologic or imaging sections. Although such 2D analyses of lung structure are considered “gold standards”, the information conveyed is often insufficient and does not represent the whole organ. Stereology, the mathematical approach to the analysis of 3D structures via 2D sampling and morphometry, the practical application of stereology, provide solutions to this problem, but had until recently not been systematically adoptedin pneumology. In an effort of minimizing the above-mentioned methodological problems and of standardizing the quantitative assessment of lung structure, the American Thoracic Society and European Respiratory Society formed a task force, which recently published its findings. The task force aimed at comprehensively reviewing current stereologic methods for lung morphometry, formulating practical guidelines for using unbiased methods for basic and translational research of lung structure, and examining the extensions of stereologic methods on non-invasive imaging of lung architecture. In the statement of the task force are included useful directives with important application in the laboratory and the clinic, the most pertinent of which are discussed in the present mini-review.