Latar belakang: Menurut estimasi, sekitar 10 juta penduduk Indonesia mengidap gagal jantung. Meskipun terdapat tatalaksana untuk mencegah memburuknya gejala, prognosis gagal jantung masih memiliki angka yang rendah. Hal ini ditandai dengan kualitas hidup yang buruk. Kepatuhan minum obat diduga dapat meningkatkan kualitas hidup pasien, sedangkan ketidakpatuhan terhadap pengobatan dapat memperburuk gejala gagal jantung. Tujuan: Untuk mengetahui hubungan kepatuhan minum obat dengan kualitas hidup pasien HFrEF di Siloam Hospitals Lippo Village Gedung B. Metode: Penelitian ini menggunakan desain studi cross sectional. Pengumpulan data dilakukan dengan penyebaran kuesioner MMAS-8 dan KCCQ-12 pada 130 responden pasien HFrEF di poli jantung rawat jalan Siloam Hospitals Lippo Village Gedung B. Data yang telah terkumpul dianalisa menggunakan metode Chi-square. Hasil Penelitian: Dari 130 sampel, terdapat 7 responden dengan kepatuhan minum obat rendah yang memiliki kualitas hidup sangat buruk-sedang dan 15 responden yang memiliki kualitas hidup sedang-sangat baik. Pada kelompok sampel dengan kepatuhan sedang-tinggi, terdapat 11 responden memiliki kualitas hidup sangat buruk-sedang dan 97 responden memiliki kualitas hidup sedang-sangat baik. Berdasarkan hasil penelitian menggunakan metode Chi-square, ditemukan hubungan yang signifikan (p-value=0,014) antara kepatuhan minum obat dengan kualitas hidup pasien HFrEF di Siloam Hospitals Lippo Village Gedung B. Kesimpulan: Terdapat hubungan yang signifikan antara kepatuhan minum obat dengan kualitas hidup pasien HFrEF di Siloam Hospitals Lippo Village Gedung B (p-value=0,014; OR=4,115) / Background: According to estimates, around 10 million Indonesians suffer from heart failure. Even though there are various treatments to prevent the worsening of symptoms, the prognosis for heart failure is still low, which is characterized by poor quality of life. Medication adherence is thought to improve the patient's quality of life, while non-adherence to medication may worsen the symptoms of heart failure. Objective: To determine the relationship between medication adherence and quality of life of HFrEF patients at Siloam Hospitals Lippo Village Building B. Method: This research uses a cross-sectional study design. Data was collected by distributing MMAS-8 and KCCQ-12 questionnaires to 130 respondents of HFrEF patients at the Siloam Hospitals Lippo Village outpatient cardiac clinic, Building B. The collected data was analyzed using the Chi-square method. Results: Of the 130 samples, 7 respondents with low medication adherence had a very poor-moderate quality of life, and 15 respondents had a moderate-very good quality of life. In the sample group with moderate-high adherence, 11 respondents had a very poor-moderate quality of life, and 97 respondents had a moderate-very good quality of life. Based on the Chi-square test results, a significant relationship (p-value=0,014) was found between medication adherence and the quality of life of HFrEF patients at Siloam Hospitals Lippo Village Building B. Conclusion: There is a significant relationship between medication adherence and the quality of life of HFrEF patients at Siloam Hospitals Lippo Village Building B (p-value=0,014; OR=4,115).