We aimed to evaluate the expression profiles of five circulating lncRNAs (HOTAIR, MALAT-1, XIST, SNHG15, and H19) in DLBCL patients and explore potential associations between their expression and different clinicopathological features. Diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma (NHL), exhibits marked genetic and clinical heterogeneity, emphasizing the need for improved tools for risk stratification. Long non-coding RNAs (lncRNAs) emerged as regulators in different cellular processes and have been linked to cancer pathogenesis. Real-time quantitative PCR (qRT-PCR) was used to evaluate lncRNA expression in the plasma of 65 newly diagnosed adult DLBCL patients and 30 age-matched controls. HOTAIR expression was significantly elevated in DLBCL patients, while SNHG15 was significantly downregulated. Interestingly, both HOTAIR and SNHG15 demonstrated robust discriminatory power between DLBCL and healthy individuals, achieving area under the curve (AUC) values of 69% and 71%, respectively. H19 expression displayed a significant association with early-stage (stage I) DLBCL. While upregulated HOTAIR was a significant independent predictor of poor prognosis, high SNHG15 expression appeared to have a protective effect on mortality rates. Our findings suggest that circulating lncRNA expression patterns are promising tools as non-invasive biomarkers for diagnosis of DLBCL. Specific lncRNAs, such as HOTAIR, SNHG15, and H19, could offer potential for disease staging and patient prognosis. Long-term follow-up studies are recommended to further elucidate the interplay between these lncRNAs and survival rates, as well as their interactions with other genetic and pathological features of DLBCL.