Background: It is usually difficult to differentiate between the pollens of different grass species on the basis of their appearance under a microscope, as they often appear similar. Such distinctions are important when interpreting the clinical relevance of pollens in air samples as individuals can differ in their allergic responses to different grass species. As this allergenic distinction occurs at the level of presence and differences of epitopes on the allergens associated with different species, it could be anticipated that species–specific monoclonal antibodies could provide such distinctions between pollens. Method: Monoclonal antibodies raised against Cynodon dactylon were screened and characterised in ELISA assays and blotting, using a range of grass pollen extracts, to identify clones which were species specific. Results: The most specific monoclonal raised to C. dactylon did not react at a level of greater than 1.2% to extracts of 10 other grass pollens in a direct ELISA assay and showed no detectable cross–reactivity in a particle blotting assay. Conclusion: It has been possible to produce a monoclonal antibody that is functionally species specific to C. dactylon.