Abstract Authors: Shannon Reed, Margaret Tovar, MPH, Paula Papanek, PhD, Patricia Sheean, Deepak Kilari, MD, Katie Bylow, MD, PhD, Whitney Morelli, PhD, Melinda Stolley, PhD Background: The Men Moving Forward intervention examines a lifestyle intervention's effects on body composition among Black/African American prostate cancer survivors (AAPCS). AAPCS. To assess PA, self-report and objective measures are being used. Studies use self-report measurements due to their simplicity and low cost, however, the congruent validity of self-report PA is often questioned. This study describes PA and strength training and also compares self- report PA to accelerometry-derived PA among AAPCS at baseline. Methods: AA men with non-metastatic PC were recruited to participate in a randomized, waitlist control trial testing the efficacy of a lifestyle intervention. The 16-week group and community-based intervention was developed with and for AAPCS and is grounded in the ACS Nutrition and Physical Activity Guidelines for Cancer Survivors. Participants completed the Godin Leisure Time Physical Activity Questionnaire (GLTPAQ) which queries about moderate and vigorous activities. The study added a question about the frequency of strength training. Participants also wore a GT3X accelerometer (Actigraph) for 7 days. Only men who wore the actigraph for at least 10 hours across 4 days were included in this analysis. Troiano 2008 cut points were used to measure moderate-vigorous PA (MVPA). Pearson’s correlation was used to assess linear correlation between objectively measured and self-reported MVPA. Statistical significance was set at p<0.05. Results: 73 AAPCS with a mean age of 65.8 years ± 6.9 were included in the analyses. Mean Godin score was 23.32 +16.80 (insufficient activity) with 45.2% classified as active (Godin score >24) and 54.8% as insufficiently active (Godin score<23). 30.2% strength trained at least twice weekly. Actigraph data showed a mean of 101.19 minutes per day of MVPA and that 73.68% of participants did not meet the guideline for 150 minutes per week of MVPA. The analysis revealed a weak positive correlation (r = 0.274, p = 0.019) between actigraph-recorded MVPA and self-reported MVPA. Conclusion: Study results suggest AAPCS overestimate their MVPA using the GLTPAQ when compared to accelerometry. Notably, a significant proportion did not meet the recommended level of physical activity. These findings underscore the importance of including objective measures of PA and the value of programming that is intentionally inclusive of AAPCS. To better support validity and reliability, participant perceptions of PA time and intensity may require improved clarification and description in studies relying solely on SR questionnaires. Citation Format: Shannon Reed, Margaret Tovar, Paula Papanek, Patricia Sheean, Deepak Kilari, Whitney Morelli, Katie Bylow, Melinda Stolley. Physical Activity in African American Prostate Cancer Survivors and a Comparison of Self-report versus Accelerometer-Derived Measurement [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B062.