After Kosić’s death, because of the large number of natural history and other objects that the Museum had collected, there was a clear need for new premises. In 1932 the Museum moved into its newly arranged quarters of the first floor of Fort St John and changed its name to Dubrovnik Museum. The natural history, cultural history, archaeological, ethnographic and maritime collections were hived off into separate departments. After in 1950 the Museum had acquired other exhibition spaces, the natural history section occupied the whole of the first floor of Fort St John.
But as early as 1952, the decision was made to move the natural history department to the Crijević-Pucić Palace, and from a department it developed into the Natural History Museum. Because of the vigorous collection of new materials and the making of dioramas, these premises too became inadequate. In 1957 the Museum was merged with the Yugoslav Academy of Sciences and Arts Biology Institute into a cultural and educational institution, after which it moved to the building of the former Benedictine monastery on Lokrum, where, in 1962, it was officially opened to visitors. The earthquake of 1979 considerably damaged the monastery building, and so the Museum was closed, the collections being stored in Fort St John. Not long after that, the Museum found itself without any professional staff.
In early 2009, the Dubrovnik Natural History Museum was founded again, and the grand opening in the Andrović Palace came in March of the same year.