BACKGROUND: The Knee Injury and Osteoarthritis Outcome (KOOS), JR is a patient-reported outcome measure that is validated for patients undergoing total knee arthroplasty. The objective of this study was to provide normative data for the KOOS, JR in a relatively healthy US population visiting an outpatient orthopedic setting. This study is a cross-sectional study. METHODS: Normative data from the KOOS questionnaire was used to calculate the subscale (pain, activity of daily living, and symptoms), raw, and interval scores for the KOOS, JR. The participants who completed the KOOS were devoid of current complaints of the hip, knee, and ankle. The means, standard deviations, medians, interquartile ranges, and percentiles for the KOOS, JR subscale, raw and interval scores were calculated by age decades, sex, laterality, and history of knee injuries in the past year. RESULTS: Four hundred two men and 598 women were involved in the analysis. The lowest mean interval scores were noted in the 56- to 64-year group with the greatest disparity between male and female compared to the rest of the age cohorts. Females scored high in all 3 subscales with a higher score in the pain subscale, denoting a lower normative value. Patients with hypertension scored with a significantly lower mean interval score than those without hypertension. In all subscales, tobacco use and hypertension were associated with a statistically significant negative effect on the normative scores. CONCLUSION: The normative values for the KOOS, JR can be used to set goals and follow the progress of patient satisfaction in regard to the knee after a knee arthroplasty procedure.