Background: Reports suggest that HIV-infected patients have elevated D-dimer levels that may be related to chronic inflammation and coagulation abnormalities. Levels of D-dimer have also been reported to be higher in HIV treatment-naïve patients compared to treatment- experienced patients. Methods: Eighty (80) subjects attending HIV clinic at the University of Port-Harcourt Teaching Hospital, Port Harcourt, Rivers state who satisfied the inclusion criteria were enrolled into the study. A commercial assay kit; ELISA Kit for D-Dimer (D2D) (manufactured by Uscn Life Science IncorporatedR USA) was used with a TC96+ ELISA microplate reader (manufactured by Ceco diagnosticR USA) to determine the D-dimer level. CD4 + T-cell count was evaluated using the Partec Cyflow counter-1, a single-platform, three-parameter (SSC plus two-colour fluorescence) desktop volumetric flow cytometer (manufactured by Sysmex PartecR Germany).Full blood count was carried out on the EDTA anticoagulated sample using the Horiba Abx Micros 60 Haematology Analyser (manufactured by Horiba instruments incorporatedR USA). Results: The D-dimer level was found to be lower in HAART- experienced subjects (288.35 ± 129.12 ng/ml) than HAART-naïve subjects (389.85 ± 217.61ng/ml.) (P= 0.013).There was no increase in haematocrit, while the mean WBC count showed increase in the HAART-experienced compared to HAART-naïve subjects. Platelet counts were also increased in the HAART-experienced subjects in comparison to HAART-naïve subjects. Conclusion: This study suggests that D-dimer levels are higher in HIV treatment-naïve patients compared to treatment- experienced patients.