Although the cyclotron has been used primarily as a source of energetic particles, it can also be used as an extremely sensitive mass spectrometer to detect radioisotopes for dating purposes. Radioisotope dating is a special case of trace element analysis. The cyclotron is tuned to accelerate the isotope of interest and the sample is introduced into the ion source. The accelerated ions with the proper signature are counted. The greatest gains over radioactive dating are achieved for the longer-lived isotopes, and the technique is most powerful for elements at the low end of the periodic table, for which relatively large beam currents can be obtained. An extended discussion of carbon-14 dating is provided, leading to the conclusion that it may be possible to extend the technique back to 100,000 years, and to use much smaller samples. A problem is the need to separate Nitrogen-14 from Carbon-14 (the two have the same charge to mass ratio). Several approaches to a solution are discussed. Also discussed are Beryllium-10 detection, dating based on two isotopes, trace element detection, and principles and results of tritium dating experiments. Cyclotrons may not be particularly expensive as dating tools when the low operating cost and rapid sample throughput are considered.