Flow cytometry represents a powerful method for the analysis of cell functions and has therefore been applied in all fields of biomedical research including respiratory research. Some specific aspects have to be considered when investigating cells from the lung that include preparation and analysis of cells from different lung compartments and problems evoking due to high autofluorescence of alveolar macrophages. The present short review discusses these issues and, in addition, gives an example for a recently developed application of flow cytometric analysis in the field of lung research that allows the differentiation between resident and newly infiltrated alveolar macrophages. (c) 2006 Elsevier GmbH. All rights reserved.