The decay of five radionuclides used as calibration sources in cosmogenic radionuclide studies was followed for from 3 to 11 half-lives. Least-squares analyses of the gamma-ray counting data yielded the following half-life values: 7Be, 53.0 ± 0.3 days; 46Sc, 84.34 ± 0.13 days; 54Mn, 312.6 ± 0.8 days; 56Co, 78.4 ± 0.5 days; and 65Zn, 244.3 ± 0.4 days.