Introduction – Lymphoblastic lymphoma (LBL) is a highly aggressive malignancy composed of immature lymphocytes of B- cell or T-cell origin. LBL is typically distinguished from acute lymphoblastic leukemia (ALL) by the presence of fewer than 20% bone marrow blasts. This retrospective multicenter cohort study evaluated the clinical data of adult LBL patients diagnosed and treated at tertiary centers in Türkiye. Materials and methods – Thirty-eight patients from seven tertiary adult hematology clinics were included. Eligible patients were ≥18 years of age, had a pathologically confirmed diagnosis of LBL, underwent radiological staging, and received at least one chemotherapy regimen. Results – The median overall survival (OS) for the entire cohort was 23 months. No statistically significant difference in OS was observed between patients with T-LBL and those with B-LBL (p>0.05). The median progression-free survival (PFS) was 6 months. The 5-year OS rate was 6%, underscoring the aggressive nature of adult LBL. Discussion – Our findings suggest exploratory univariate associations between certain clinical features and inferior OS. Elevated LDH levels, central nervous system involvement, disease affecting ≥3 anatomical regions, cervical lymphadenopathy, failure to achieve remission after initial therapy, and male gender may correlate with poorer outcomes. These results should be interpreted cautiously given the limited sample size and reliance on univariate analyses.