Background HIV-RNA is the most important parameter for monitoring antiviral treatment in individuals infected with HIV-1. Knowledge of the performance of different tests for the quantification of HIV-1 RNA is therefore important for clinical care. Objectives To compare the analytical performance of the Aptima HIV-1 Quant Dx Assay (Aptima) and the COBAS Ampliprep/COBAS TaqMan HIV-1 Test v2.0 (CAPCTMv2) for the quantification of HIV-1 RNA in plasma samples. Study design The performance of the two tests was compared on 216 clinical plasma samples, on dilutions series in seven replicates of five clinical samples of known subtype and on ten replicates of the Acrometrix High and Low Positive Control. Results Bland-Altman analysis of 130 samples that quantified in both tests did not show indications of gross mis-quantification of either test. A tendency of the Aptima assay to quantify higher at high viral load compared to the CAPCTMv2 was observed in Bland-Altman analysis, by Deming regression (Slope 1.13) and in dilution series of clinical samples. Precision evaluated using the Acrometrix Positive Controls was similar for the High Control (CV: 1.2% vs. 1.3%; Aptima assay vs. CAPCTMv2 test, respectively), but differed for the Low control (CV: 17.9% vs. 7.1%; Aptima assay vs. CAPCTMv2 test, respectively). However, this did not impact clinical categorization of clinical samples at neither the 50 cp/mL nor 200 cp/mL level. Conclusion The Aptima assay and the CAPCTMv2 test are highly correlated and are useful for monitoring HIV-infected individuals.