The aim of the study was to determine the most useful tests for decision making in the diagnosis of asthma in patients with dyspnea assessed by commonly used terms: sensitivity, specificity, positive and negative predictive values and diagnostic accuracy. In a group of 195 patients with dyspnea data were analyzed with respect to case histories and different diagnostic procedures: bronchial hyperresponsiveness (BHR), skin prick tests (SPT), total IgE, spirometry (FEV1), sputum eosinophils (SE) and blood eosinophilia (BE). Asthma was diagnosed in 141 subjects. The control group comprised 18 subjects. Sensitivity for BHR in asthma in subjects with dyspnea amounted to 97%, for SPT to 62%, while all other diagnostics were lower than 50%. Specificity was highest for SE (94%), and BHR (85%). Positive predictive value (PPV) in asthma was for BHR 94%, for SE 86%, for SPT 81%, for decreased FEV1 79%, total IgE 72% and BE 64%. The highest negative predictive value (NPV) was found for BHR (92%). Diagnostic accuracy was highest for BHR 93% and for SPT 62%, while all other tests were comparable or lower than 50%. It is not possible to conclude whether or not a person has asthma merely on the basis of data on skin sensitization to aeroallergens, total IgE, eosinophils or lung function tests. Bronchial hyperresponsiveness showed the highest values for sensitivity (97%), PPV (94%), NPV (92%) and accuracy (93%). The second most efficient test is the skin prick test, with PPV 81% and diagnostic accuracy 62%.