Context: The effect on mortality of screening for lung cancer with modern chest radiographs is unknown. Objective: To evaluate the effect on mortality of screening for lung cancer using radiographs in the Prostate, Lung, Colorectal, andOvarian (PLCO) Cancer Screening Trial. Design, Setting, and Participants: Randomized controlled trial that involved 154 901 participants aged 55 through 74 years, 77 445 of whom were assigned to annual screenings and 77 456 to usual care at 1 of 10 screening centers across the United States between November 1993 and July 2001. The data from a subset of eligible participants for the National Lung Screening Trial (NLST), which compared chest radiograph with spiral computed tomographic (CT) screening, were analyzed. Intervention: Participants in the intervention group were offered annual posteroanterior view chest radiograph for 4 years. Diagnostic follow-up of positive screening results was determined by participants and their health care practitioners. Participants in the usual care group were offered no interventions and received their usual medical care. All diagnosed cancers, deaths, and causes of death were ascertained through the earlier of 13 years of follow-up or until December 31, 2009. Main Outcome Measures: Mortality from lung cancer. Secondary outcomes included lung cancer incidence, complications associated with diagnostic procedures, and all-cause mortality. Results: Screening adherence was 86.6% at baseline and 79% to 84% at years 1 through 3; the rate of screening use in the usual care group was 11%. Cumulative lung cancer incidence rates through 13 years of follow-up were 20.1 per 10 000 personyears in the intervention group and 19.2 per 10 000 person-years in the usual care group (rate ratio [RR]; 1.05, 95% CI, 0.98-1.12). A total of 1213 lung cancer deaths were observed in the intervention group compared with 1230 in usual care group through 13 years (mortality RR, 0.99; 95% CI, 0.87-1.22). Stage and histology were similar between the 2 groups. The RR of mortality for the subset of participants eligible for the NLST, over the same 6-year follow-up period, was 0.94 (95% CI, 0.81-1.10). Conclusion Annual screening with chest radiograph did not reduce lung cancer mortality compared with usual care. Trial Registration: clinicaltrials.gov Identifier: NCT00002540. ©2011 American Medical Association. All rights reserved.