Mass cytometry is a new technology that can perform simultaneous analysis of 40 or more parameters in single cells via mass spectrometry and heavy metal conjugated antibodies. It has been successfully utilized for the simultaneous analysis of complex cellular types and intracellular signaling pathways. However, mass cytometry reagents were unavailable for analyzing proliferation and cell cycle, which are critical to the study of cell biology, in particular cancer and tumorigenesis. To address this, Behbehani and coworkers have developed a new methodology for mass cytometry to measure all phases of the cell cycle simultaneously within complex samples, while simultaneously measuring up to 30 additional parameters. The addition of cell cycle analysis greatly increases the utility of mass cytometry for all fields, and will only increase the rate of adoption for this exciting new technology.