Abstract While using samples of 24Na as photon sources for high-precision studies of Delbrück scattering, the adopted half-life of this nucleus was found to be incorrect. Since the precise half-life is required for the evaluation of the Delbr̈uck scattering data, a remeasurement was carried out using a Ge(Li)-detector. The decay of three samples of 24Na, produced in the Göttingen cyclotron by the reaction 27 Al( d, α p) 24 Na , was followed over 10 half-lives. Two of the samples contained 24Na in the lattice of metallic aluminum while the third sample was an acid solution of 24NaNO 3. In both cases the result was T 1 2 = (14.964 ± 0.015) h .