Hemoglobin of bony fish and higher vertebrates is a tetrameric protein constructed by 2 α- and 2 β-globins, which are expressed in a developmental stage-specific manner. The genomic organization of genes for embryonic and adult α- and β-globin varies from species to species. In fish, it is known that there is a unique genomic organization of globin genes, that is, α- and β-globin genes are arranged in a bi-directional and head-to-head orientation with respect to transcription start sites. In medaka, we have demonstrated that 14 globin genes are located in 2 different clusters, and 5 pairs of the α- and β-globin genes were found to be organized in a head-to-head orientation. The developmental expression patterns of the 11 globin genes were classified into 4 types. To clarify how their developmental stage-specific expressions are regulated, we produced 4 types of GFP- or RFP-transgenic medaka. Such transgenic medaka revealed that each of the 1-1.7 kbp 5' upstream sequences from respective globin genes possesses the ability to regulate the developmental stage-specific globin gene expression. In particular, the intervals between head-to-head α3 and β3, and α4 and β4 genes controlled the synchronized expression of the globin genes located at both sides of the intervals, which is significant to understand the mechanism by which equal amounts of α- and β-globins are expressed in erythroid cells. We also demonstrated that the head-to-head intervals can control the expression of the globin genes located at both sides. These findings are significant to understand the mechanism by which α- and β-globins are equally expressed in erythroid cells.