Introduction: The role of cross-reactive carbohydrate determinants (CCDs) in diagnostics of occupational allergy remains unclarified and its clinical relevance is still questioned. The aim of the study was to assess the frequency of positive response to CCDs in the subjects with suspected occupational allergy and the relationship between other diagnostic test results and final diagnosis. Material and methods: The study group included 201 patients. They underwent clinical examination, skin prick test (SPT) to common and occupational allergens, specific serum immunoglobulin (sIgE) determinations, spirometry and specific inhalation challenge test. Moreover, sIgE to CCDs from bromelain was assessed in all subjects. Results: Occupational respiratory allergy was recognized in 64.3% of CCD-positive and 52.4% of CCD-negative patients. Positive SPT results to common and occupational allergens were found in 64.3% and 35.7% of CCD-positive subjects, respectively. In all subjects with CCDs, the sIgE to grass pollens as well as to occupational allergens were detected. The total IgE level > 100 kU/l was significantly associated with the presence of sIgE to CCDs. Conclusions: sIgE to CCDs were found in 7% of subjects suspected to suffer from occupational respiratory allergy. The presence of CCDs is not significantly associated with occupational respiratory allergy. It is also not more frequent in subjects reporting work-related respiratory symptoms in whom occupational allergy was not confirmed. The elevated total IgE level was related with CCD positivity. In patients with suspected occupational allergy, the presence of sIgE to CCDs in serum did not indicate the irrelevance of positive sIgE to occupational allergens.