According to recent advances it is assumed that the gastroesophageal reflux (GER) is a possible co-promoting factor of the squamous-cell carcinoma development in the upper parts of the gastro-intestinal and respiratory systems, considering the higher frequency of lesions due to acid in the studied population interested by GER. The aim of this study is to investigate 274 patients with malignant neoplasm of the oral cavity, of the pharynx and of the larynx, by esophago-gastro-duodenoscopy (EGD) and to compare the incidence of GER in this group with a control group of healthy patients from their hospital. Acid exposure in the upper level of the esophagus often remains unknown using traditional pH-monitoring, especially if no pharyngeal probe is used. When necessary a good diagnostic test is EGD with mucosa biopsy; it allows to directly examine the lesion. We retrospectively studied the data of 274 patients suffering from a cancer of the upper aero-digestive tracts by EGD in order to diagnose lesions caused by GER. We compared non-smoking patients affected by GER and tumours a control group of healthy patients. Statistical analysis revealed a significant difference between the two groups using the z-Test (p = 0.0001). In our study, based on endoscopic data, we observed a high percentage of non-smoking patients affected by GER and squamous-cell carcinoma of the upper parts of the airways and the gastrointestinal system. For this reason we consider GER as a possible co-promoting factor of cancer in some patients.