The nucleocapsid protein NCp7 of HIV-1 possesses nucleic acid chaperone properties that are thought to be crucial throughout the viral life cycle. These properties promote the rearrangement of nucleic acids into their most thermodynamically stable conformations. These NCp7 properties involve two components, namely nucleic acid destabilization and activation of the annealing of complementary sequences. Biophysical techniques have been found extremely powerful to decipher the molecular mechanisms underlying these two components. We propose here an overview of the recent reports that examine the nucleic acid chaperone properties of NCp7 by these techniques.