The objective of this study is to describe a case-series of potassium aluminium tetrafluoride (KAlF4)-induced occupational asthma (OA) and/or occupational rhinitis (OR). The study involves five patients from a heat-exchanger production line who were examined (including specific inhalation challenge tests) for suspected OA and/or OR caused by a flux containing almost 100% KAlF4– with fluorides‘ workplace air concentrations ranging between 1.7 and 2.8?mg/m3. No subject had a previous history of asthma. All five patients had a positive specific challenge test (three patients were diagnosed with OA alone, one with OR and one with both OR and OA). At the follow-up visit, after three years on average, all patients needed permanent corticosteroid therapy (four topical, one oral). After elimination from the exposure, only one of the observed subjects gave an indication of an improvement, two subjects stabilized and two worsened. Our case series focuses on the correlation between patients’ exposure to fluorides in air-conditioner production and the subsequent occurrence of OR/OA. Currently, it is uncertain whether these OR/OA were caused by hypersensitivity or irritation.