Paper Products Abstract A genetic system, ProTracer, has been recently developed to record cell proliferation in vivo.However, the ProTracer is initiated by an infrequently used recombinase Dre, which limits its broad application for functional studies employing floxed gene alleles.Here we generated Cre-activated functional ProTracer (fProTracer) mice, which enable simultaneous recording of Flash Drives 32GB cell proliferation and tissue-specific gene deletion, facilitating broad functional analysis of cell proliferation by any Cre driver.