Ist Island is one of the small inhabited Croatian islands (9.65 km2) which experienced strong socio-geographic transformation in the second half of the 20th century. Statistical data about the number of population, different demographic structures, dwellings from different censuses and data about land use in 1900, 1951 and 2003 are analysed in the paper. The comparison of these data helps to reconstruct the processes of deruralization and deagrarisation. It is obvious that today Ist Island is among islands with strong economic regress despite suitable natural-geographic basis for further development of tourism as the most perspective economic sector. The development of agriculture is limited because of the small share of arable land.