Primary intramedullary spinal cord tumors are a rare entity, comprising 4–10 %of all spinal cord tumors. The current report presents data on intramedullary spinal cord anaplastic astrocytomas and glioblastomas in adults using the national surveillance, epidemiology, and end results database (1973–2008), and evaluates the impact of demographic and treatment factors on survival. Eighty nine adults were evaluated (mean age of 43 years); 49 % of patients had anaplastic astrocytoma and 51 % of patients had glioblastoma.88 % of patients had surgical intervention and 85 % of patients had radiotherapy. In univariate analysis, male gender (HR = 0.50, CI: 0.29–0.86, P = 0.01), surgical treatment (HR = 0.37, CI: 0.15–0.93, P = 0.03), and tumor histology (HR = 1.83, CI: 1.06–3.18, P = 0.03) were significant predictors of survival. Results remained significant or marginally significant after multivariate adjustment analyses. Adjuvant radiotherapy and age at diagnosis did not have a significant influence on survival. Future prospective studies from collaborative institutions combining richer detail in perioperative treatment, radiotherapy dosing, chemotherapy treatment, neurologic examinations, functional outcomes, and quality of life measures would contribute to more concrete, evidence-based treatment protocols for adult patients with primary malignant spinal cord astrocytomas.