This study investigates whether modifying the instructions of the Posttraumatic Stress Disorder Checklist (PCL) for military survey research changes posttraumatic stress disorder (PTSD) symptom reporting or prevalence. The sample consisted of 1691 soldiers who were randomly assigned to complete 1 of 3 versions of the PCL, which differed only in the wording of the instructions. Group differences in demographic variables, combat exposure, mean PTSD symptoms, and PTSD prevalence estimates were examined. Results showed that there were no statistically significant differences in the outcomes across the PCL versions. The findings indicate that researchers may make modifications to the PCL instructions to meet research needs without affecting PTSD symptom reporting or prevalence estimates.