Ribosomes have been visualized in electron micrographs in 1943 but 5S rRNA was discovered 20 years later. The next four decades witnessed big advances in our understanding of the ribosome using biochemical, genetic and low resolution structural approaches. During those times many experimental data accumulates also on 5S rRNA, but its precise function remains unknown. To understand the role of this RNA in ribosome a high-resolution structure is urgently needed. Because the ribosome is a dynamic machine, details on the interaction of 5S rRNA with proteins within entire ribosome are required. Big progress in the structural analysis of ribosome will stimulate further understanding of 5S rRNA.