Fifty-one fish meal factory workers in four Polish harbour cities were investigated. They had been employed in the fish meal factory for 1--33 years and 10.7 years on average. All but seven of these were smokers. The investigation consisted of respiratory symptoms questionnaire, chest X-ray, physical examination, respiratory function assessment, intradermal skin tests to ten fish genera, total serum IgE and serum precipitins to fish antigen assessment. Chronic bronchitis was diagnosed in 29 investigated patients. In 12 (23%) of the patients, according to their case history or to skin tests, allergy to fish was suspected, but was confirmed by elevated serum IgE levels in only two of these. In no cases were serum precipitins against fish antigen found. In six patients, either obstructive or restrictive changes were diagnosed according to conventional spirometry, but by MEF50% VC in 17 subjects (33%) slight airways obstruction was diagnosed and can be regarded as the result of the habit of smoking. According to the performed investigation, only two workers presented a full clinical and immunological picture of allergy to fish. From the practical point of view, this type of professional activity is less dangerous than might be theoretically expected.