Background: Malignancies often affect the nervous system and causes considerable neurologic morbidity and mortality. These effects may directly involve the brain, spine, or peripheral nervous system (PNS) or indirectly affect the nervous system such as paraneoplastic neurologic syndromes. Objective: This study aimed to detect the prevalence of neurological manifestation among hematologic malignancies patients in relation to their treatments’ outcomes. Subjects and methods: This retrospective medical record-based study was performed on all patients with hematologic malignancies who were admitted to King Abdulaziz University Hospital from 2009-2016. Results: Out of 138 (36.9%) patients with hematologic malignancy showed neurological manifestation after radiotherapy or chemotherapy. The most common neurological manifestations were headache (13.6%), dizziness (8.3%) and back pain (7.8%). Death occurred in 21.2% of patients with neurological manifestations versus 13.9% in patients without neurological manifestations. The mortality rate in patients with headache, change in cognition, limb thickness and stroke were 38.5, 38.5, 26.9 and 23.1% respectively. The mortality rate was significant higher (p<0.001) among older patient than others. Conclusion: this study threw the light on the prevalence of neurological manifestations in patients with hematologic malignancies. this is important for the neurologists as well as hematologists and anyone involved in treating patients with hematologic malignancies to be aware of such neurological manifestation and how to diagnose and treated it in order to help provide a better quality of life for those patients.