The normal human Y chromosome was subdivided into 6 distinct bands by Q, C bandings and microdensitometric tracing. The best results were obtained from chromosomes not fully condensed. The results reveal that at late prophase the Y can be subdivided in 1 single unstained band in short arm 5 bands in the long arm. These 5 bands from centromere to telomere are: a pericentric C+ band Yq1; unstained band Yq2; C+ band Yq3; lightly stained band Yq4; and a C+ band Yq5. These observational results were substantiated by densitometric tracings. The Yq3 and Yq5 bands can sometimes be subdivided further into a dark and a light C+ zone. The Q band analysis indicates that the distal heterochromatin can be subdivided in two regions with the Yq4 band appearing as a lightly stained zone. We believe the terminal heterochromatin of the prevalent human Y represents a single tandem duplication.