The analysis of erythrocyte morphologic characteristics in urine using a hematologic flow cytometer and microscopic methods. Three methods for the examination of erythrocyte morphology in urine are described: phase contrast microscopy, microscopy of cytocentrifuged and stained preparations, and erythrocyte analysis with the Technicon H1. Analysis with the H1 has not been described until now. All methods can be used to discriminate between dysmorphic and isomorphic erythrocytes. The red cell distribution width was the best H1 parameter for this discrimination. The authors have found a good correlation between the microscopic methods. The clinical impact of the three methods was studied with urine samples from patients with a confirmed diagnosis. The discrimination between renal and nonrenal hematuria is similar with phase contrast microscopy and cytocentrifuged preparations. The use of the H1 for this discrimination is not recommended. 