Background <p>Long-term tenofovir disoproxil fumarate (TDF) administration has been associated with potential adverse effects on renal function. Pegylated interferon-α2 (PEG-IFN-α2) therapy in chronic hepatitis B (CHB) patients increased estimated glomerular filtration rate (eGFR). Thus, the aim of this study was to analyze the influence of PEG-IFN-α-2b add-on to on-going TDF therapy in renal function in CHB patients.</p> Methods <p>This was a retrospective observational study. Ninety-one CHB patients who were treated with TDF for more than 48 weeks, had hepatitis B surface antigen (HBsAg) &lt; 1500 IU/mL, and were hepatitis B e antigen-negative were recruited. Sixty-seven patients continued TDF monotherapy, and twenty-four patients received PEG-IFN-α-2b add-on therapy. Renal function indices were collected at baseline, 12 weeks, 24 weeks, and 48 weeks post-therapy. A linear mixed effects model for repeated measures was employed to analyze the associations between baseline information and serum β2-microglobulin (β2-MG)/urine α1-microglobulin (α1-MG) changes.</p> Results <p>HBsAg clearance rate was higher in TDF + PEG-IFN group compared with TDF monotherapy group (20.83% vs. 0.00%). There were no significant changes in blood urea nitrogen (BUN), creatinine (Cr), or eGFR in TDF monotherapy group. BUN and Cr was down-regulated, while eGFR was up-regulated at 48 weeks in TDF + PEG-IFN group. In TDF monotherapy group, serum β2-MG was elevated at 12, 24, and 48 weeks, whereas no significant changes were observed in TDF + PEG-IFN group. Serum β2-MG was higher in TDF monotherapy group than in TDF + PEG-IFN group. Urine α1-MG was increased in both groups at 48 weeks. TDF monotherapy was positive predictor for serum β2-MG increase, while TDF + PEG-IFN therapy negatively affect serum β2-MG level. Both TDF-based therapeutic strategies were positive predictors for urine α1-MG elevation.</p> Conclusion <p>PEG-IFN-α-2b might exert a protective effect against TDF-induced glomerular injury in CHB patients.</p>