The present study was conducted for the purpose of determining the main feeding aspects of the brushtooth lizardfish Saurida undosquamis. It was carried out from September 2018 till April 2019 in the Northern Gulf of Suez, and from March 2018 to March 2019 in the South-Eastern Mediterranean Sea at Port Said. A total of 1110 specimens were monthly collected from both sites. The analysis of stomachs content showed that S. undosquamis is a carnivorous species, feeding on some of both vertebrates and invertebrates preys. The seasonal variations in diet composition revealed that fish remains were the most dominant food item for both populations; however, not during all seasons. Regarding the intensity of feeding, individuals with stomachs containing food were observed mostly during winter with a percentage of 71.4%, while their maximum percentage was in spring with 80.3% for the Gulf of Suez and the Mediterranean Sea populations, respectively. On the other hand, the degree in fullness followed a different trend for individuals from both populations. The variations of diet composition in relation to size for both populations showed that fish remains were the most abundant food items for specimens of almost all size classes, and the monthly averages of gastro–somatic index indicated that both study sites had fluctuation in values.