The current knowledge of both glass-making and glass-working in Ptolemaic Egypt is very poor. Excavations and surface surveys conducted in the region of Alexandria and in the Wadi Natrun located primary glass-making furnaces, but these appear to be later productive centres, operating only since the first century CE. Presently, we do not know any earlier primary workshop and it is also difficult to understand clearly which glass objects were actually produced in Ptolemaic Egypt. The reference to Alexandria in the ancient sources, as a glass producer, has shaped a centralized model, widely accepted in literature, with the capital acting as the leading centre for both glass-making and glass-working.However, the only glass-working sites located in Ptolemaic Egypt are four workshops specialised in making both monochrome and millefiori inlays, i.e. small plaques used to decorate religious and funerary furniture and none of them is in Alexandria. A survey conducted on glasses in the collections of the Egyptian Museum of Cairo allowed to identify a new large assemblage of glass finds, interpretable as glass-working waste from a further workshop making inlays, excavated in Denderah (Upper Egypt), at the beginning of the 20th century. This paper presents the preliminary results of a morphological observation conducted on unworked glass (cakes, lumps and chips from the workshop). The results suggest a technological continuity with LBA Egyptian tradition and the possibility that glass colouring was practiced in Denderah, inserting glass-working in the activities administrated by temples and located in the annexes.