Phase changes and equations of state of four sodium halides, NaF, NaCl, NaBr, and NaI, have been studied up to ~60 GPa at room temperature with the use of a diamond avil cell. NaF and NaCl transform from the B1 phase to the B2 phase at ~23 GPa and ~29 GPa, respectively. At ~33 GPa, NaBr transforms from the B1 phase to an unidentified phase with a lower symmetry than the B2 phase. NaI also transforms at ~32 GPa to a new phase which seems to have the same structure as that of the high-pressure phase of NaBr. The B2 phase of NaF has bulk modulus K0=103 (¿19) GPa and volume ratio at 1 atm V02/01=0.811 (¿0.025), and B2 phase of NaCl has K0=121 (¿23) GPa and V02/V01=0.734 (¿0.022). The volume change across the transition was estimated to be ΔV/V1≂-10.4% for NaF and -5.8% for NaCl.