Cosmic-ray-produced (CP) nuclides with half-lives shorter than 21h were measured in rainwater by ultra-low-background gamma spectrometry at Ogoya Underground Laboratory. As levels of CP nuclides are extremely low and their half-lives are very short, quick sampling methods for a large volume of rainwater and rapid chemical separations by ion exchange method were developed. The nuclides measured were short-lived 24 Na, 28 Mg, 38 S, 38 Cl, 39 Cl, as well as nuclides with longer half-lives 7 Be and 22 Na. The number of atoms of CP nuclides in rainwater were evaluated to range from 30 to 1500L −1 for 24 Na (n=16, mean; 520 [6.7mBqL −1 ]), 80 to 600L −1 for 28 Mg (n=13, mean; 260 [2.4mBqL −1 ]), 400 to 1900L −1 for 39 Cl (n=6, mean; 1200 [250mBqL −1 ]), 1×10 6 to 4×10 7 L −1 for 7 Be (n=16, mean; 7×10 6 [1.05BqL −1 ]) and 2×10 3 to 1×10 5 L −1 for 22 Na (n=9, mean; 2×10 4 [0.2mBqL −1 ]).