Occupational rhinitis is a work-related disease that results from nasal exposure to toxic and harmful substances in the workplace. Both allergic and nonallergic mechanisms may be involved. It has a very typical presentation and worsens with continued exposure. There is a very wide list of substances that cause this disease, mainly products associated with ammonia. The diagnosis is made based on the clinical manifestations and the first line treatment is the cessation of exposure. The authors present a case report of a 52-year-old woman, who worked as laboratory assistant in techniques of biology, physics and chemistry, in a secondary school, for 20 years. Preparation of ammoniacal solutions and solutes in association with the manipulation of the products without personal protective equipment, led to the development of a clinical picture compatible with the diagnosis of occupational rhinitis. In the clinical history, the symptomatology described by the patient worsened in periods of labor exposure and was absent in vacation periods, which is typical of occupational pathology. Several treatments were attempted, medical and surgical, before occupational rhinitis was suspected. However, improvement of the clinical picture with work reallocation, led to the assumption that occupational rhinitis was the most likely diagnosis. This case demonstrates that the diagnosis of occupational rhinitis can be easily missed, if we ignore the occupational exposure of patients, which can lead to unnecessary and costly medical interventions, since the only effective treatment is the cessation of exposure to the causal agent.