Purpose <p>This study aims to emphasize the importance of sexual health in older adults with hematologic malignancy (HM) in Denmark by exploring the prevalence of sexual symptoms and factors that influence sexual activity and function.</p> Methods <p>A sub-analysis of a Danish cross-sectional study including older adults (≥ 65&#xa0;years) diagnosed with a HM from 20/1–2013 to 20/8–2022. Eligible participants received electronic validated questionnaires about quality of life, sexuality, and sexual health in their officially assigned digital mailbox.</p> Results <p>Decreased libido, impaired sexual activity, diminished confidence in erection, vaginal dryness, and reduced sexual satisfaction were among the most reported sexual symptoms. Interestingly, 93% of participants reported that sexual health had never been discussed with healthcare professionals. A significant correlation was found between sexual inactivity and a higher degree of sexual dysfunction in both men and women. Gender comparison revealed that men experienced significantly more sexual distress than women (<i>p</i> = 0.012). Age stratification showed that men aged 65–75 had significantly better erectile function compared to those &gt; 75 (<i>p</i> = 0.031), while women aged 65–75 had better sexual arousal and orgasmic function than those &gt; 75&#xa0;years (<i>p</i> = 0.028).</p> Conclusion <p>Older adults with HM experience a high prevalence of sexual dysfunction. Men &gt; 75&#xa0;years experienced more severe erectile dysfunction, and sexual distress was particularly notable among men and patients with lymphoma. Regardless of treatment, sexual dysfunction persists in older adults with HM, emphasizing the need for continuous, supportive care addressing sexual health both during and after treatment.</p>