A solid-phase, monoclonal antibody-based ELISA was set up to quantitale group 5 allergens in pollen extracts of wild and cultivated Pooideae grasses. The method was able to evaluate group 5 concentration in mass units with a sensitivity in the ng/ml range and a practical working range of 1–100 ng/ml. The group 5 ELISA was compared with rocket immunoelectrophoresis for determination of allergen levels in several Phleumpratense extracts, and a very good quantitative correlation was found (r=0.98; P<0.0001). A highly significant correlation (r>0.8) was also obtained in comparing allergenic potency determined by RAST inhibition to group 5 content in several wild and cultivated grass species. The results proved the usefulness of the method in the standardization of Pooideae pollen extracts employed in diagnosis and treatment.