Introduction: Metastatic cancer patients report elevated stress levels and unique stressors compared to other adults. This study tested the feasibility and efficacy of a mental health app with comedy content delivered to women living with advanced cancer (WLAC). Methods: The mental health platform Neolth was used as a self-guided intervention for WLAC, ages 18+ years. WLAC were recruited by The Comedy Cures Foundation through a press release, social media posts, an email newsletter, and a video call for participants on the foundation’s website. No compensation was provided to participants. After using the Neolth platform, which included watching comedy content for eight weeks, researchers evaluated engagement, and stress levels using The Perceived Stress Scale -10 (PSS-10), self-efficacy using The New General Self-Efficacy Scale (GSES), and anxiety and depression using The Hospital Anxiety and Depression Scale (HADS-A and HADS-D). Results: 54 WLAC (M = 52.2 years, R = 31-74) from 10 countries and 24 states participated by completing the baseline questionnaire. 20.5% identified as BIPOC and 33.0% had previous experience with a mental health app. 57.4% (N=31) completed the study surveys at Week 4 and Week 8. At Week 8, HADS-D scores decreased 18.1%, PSS-10 scores decreased 15.1%, HADS-A scores decreased by 9.7%, and GSES scores increased 7.6%. Participants spent an average of 116 minutes per week on Neolth with an average of 3.15 logins per week. 43.6% of time spent was completing self-guided relaxation practices and 17.2% watching Comedy Cures Foundation videos from cancer survivor Saranne Rothberg. The 30-day retention on Neolth was 100%, with 60-day retention 83%. Conclusion: This study demonstrated the ability of a mental health app with comedy content to engage and support the mental health of WLAC, presenting a cost-effective intervention. Further examination with a larger sample size is needed to conduct multivariate analyses for enhanced understanding of the role of mobile apps and comedy content in reducing stress, anxiety, and depression for WLAC. Citation Format: Saranne Rothberg, Katherine B. Grill, Claire Wheeler. Implementation and evaluation of a mental health app with comedy content for women living with advanced cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 720.