BACKGROUND: This paper presents a comparative study of moss diversity in three collection sites in the South Shetland Islands (King George, Elephant, and Nelson Islands) and one in the Antarctic Continent (Hope Bay, Antarctic Peninsula). In the King George, Elephant, and Nelson Islands, the collections were done in ice-free areas during the austral summers of years 1988,1989, 1990, 1991, 1992, and 1994. In Hope Bay, the collections were done in the 2009 summer (February). All collections were deposited in the HCB (Chaves Batista Herbarium). FINDINGS: The King George Area is the most diverse area and the Hope Bay has the lowest diversity stats. The diversity stats for each region and the similarities between both are presented. CONCLUSION: This results suggested that harder climatic conditions determine lower diversity for the bryoflora.