In this paper, modern definition of island established by the IHO has been accepted, and classification of islands, islets, rocks and rocks awash has been proposed according to their areas. The coastline of the Croatian part of the Adriatic Sea was digitized from topographic maps produced at the scale of 1 : 25 000 (TM 25). Topographic maps used for digitization are more precise than the maps that were used in earlier works and consequently the data on the number of islands and their coastline lengths and areas are more precise. Polygons of islands were closed in GIS package AutoCAD Map 2000, and each was given its name. From the obtained database and classification of islands, islets and rocks, in the coastal sea area of the Republic of Croatia 79 islands, 525 islets, and 642 rocks and rocks awash, or a total of 1246 have been recorded. Furthermore, it has been established that on TM 25 the island of Cres has the largest area (405.70 km2), although in literature so far (including atlases) the island of Krk was most often cited as the largest island in the Adriatic Sea. The island of Pag has the longest coastline length of 302.47 km.U ovom članku prihvaćena je suvremena definicija otoka utemeljena na preporukama Međunarodne hidrografske organizacije (IHO) i predložena je klasifikacija otoka, otočića, hridi i grebena prema njihovoj površini. Obalna crta hrvatskog dijela Jadranskog mora digitalizirana je sa topografskih karata mjerila 1 : 25 000 (TK 25). Topografska karta korištena za digitalizaciju je preciznija nego karte koje su korištene u ranijim radovima. Stoga je podatak o broju otoka, otočića, hridi i grebena, njihovoj duljini obalne crte i površini precizniji. Poligoni otoka zatvoreni su u GIS paketu AutoCAD Map 2000, a svakom od njih je dodijeljen naziv. Iz dobivene baze podataka i klasifikacije otoka, otočića, hridi i grebena, u obalnom moru Republike Hrvatske zabilježeno je 79 otoka, 525 otočića i 642 hridi i grebena ili ukupno 1246. Nadalje, ustanovljeno da na TK25 otok Cres ima najveću površinu (405,70 km2), iako je do sada u literaturi otok Krk najčešće navođen (uključujući i atlase) kao najveći otok u Jadranskom moru. Najdulju obalnu crtu ima otok Pag (302,47 km)
