Background Law enforcement depends on cooperation from the public and crime victims to protect citizens and maintain public safety; however, many crimes are not reported to police because of fear of repercussions or because the crime is considered trivial. It is unclear how police reporting affects the incidence of future victimization. Objective To evaluate the association between reporting victimization to police and incident future victimization. Methods We conducted a retrospective cohort study using National Crime Victimization Survey 2008-2012 data. Participants were 12+ years old household members who may or may not be victimized, were followed biannually for 3 years, and who completed at least one followup survey after their first reported victimization between 2008 and 2012. Crude and adjusted generalized linear mixed regression for survey data with Poisson link were used to compare rates of future victimization. Results Out of 18,657 eligible participants, 41% participants reported to their initial victimization to police and had a future victimization rate of 42.8/100 person-years (PY) (95% CI: 40.7, 44.8). The future victimization rate of those who did not report to the police (59%) was 55.0/100 PY (95% CI: 53.0, 57.0). The adjusted rate ratio comparing police reporting to not reporting was 0.78 (95% CI: 0.72, 0.84) for all future victimizations, 0.80 (95% CI: 0.72, 0.90) for interpersonal violence, 0.73 (95% CI: 0.68, 0.78) for thefts, and 0.95 (95% CI: 0.84, 1.07) for burglaries. Conclusions Reporting victimization to police is associated with fewer future victimization, underscoring the importance of police reporting in crime prevention. This association may be attributed to police action and victim services provisions resulting from reporting.