Abstract
Giant H II Regions (GH IIR) provide the link between the formation of massive stars at smaller scales and the violent processes of star formation that happen in starburst galaxies. This work aims to discover the presence of GH IIR in spiral and blue compact dwarf (BCD) galaxies and to analyze the properties of the ionized gas in order to determine the nature and evolutionary state of its source of energy. We have identified the giant nature of candidate regions and we have determined temperatures, densities and chemical abundances of the ionised gas. These giant H II regions lie, within errors, on the already observed regression in the L-σ plane.