The purpose of the Kaštela Municipal Museum is to encourage interest in cultural and natural heritage as well as fostering the feeling of local identity among the citizens of Kaštela.
In order to achieve this, the museum enriches its ethnographic, cultural history, archaeological and modern art collections, and is also endeavouring to cover the natural heritage by setting up a natural history collection. It deals in research work, striving to obtain a new understanding of various forms of the cultural heritage of Kaštela. The museum preserves the objects in its collections and keeps them from deterioration. With permanent and occasional exhibitions, publications and other public engagement activities, the museum interprets and presents the cultural and natural heritage of the local area. It devotes particular attention to the education of visitors and cultural campaigns, creating the conditions for an active relationship of user and museum, art and heritage in general. The museum also acts as a kind of cultural centre in which the citizens of Kaštela can occasionally see and experience the heritage of Dalmatia, Croatia and Europe. At the same time it attempts to present the Kaštela heritage at home and abroad.