Assessments of amphibian immune state have been commonly made through indirect methods like phytohemagglutinin (PHA) injections, or by direct methods like cell counts from blood smears. Here a simple method is validated to assess immune responses in amphibians by means of flow cytometry with a fluorescent lipophilic dye (3,3? Dipentyloxacarbocyanine), which removes the need for specific antibodies. Here the immunological state of Pelobates cultripes tadpoles was experimentally altered by exposing some to exogenous corticosterone. The immune state of each tadpole was then determined through both blood smears and flow cytometry. It was found that both techniques showed similar patterns of the proportion of white blood cells. Once validated, flow cytometry also allowed quantitation of changes in absolute number of white cells. The suitability of both techniques is discussed attending to the accuracy of each technique, body size requirements, or the tractability in field studies. informacion[at]ebd.csic.es: Burraco et al (2017) Validated flow cytometry allows rapid quantitative assessment of immune responses in amphibians. Amphib-reptil DOI:10.1163/15685381-00003093