OBJECTIVE To investigate the association between treatment-induced change in continuous glucose monitoring (CGM) time in range (TIR) and albuminuria in persons with type 1 diabetes (T1D) treated with sensor-augmented insulin pumps (SAP). RESEARCH DESIGN AND METHODS Twenty-six out of 55 participants with albuminuria and multiple daily injection therapy (25% females; median 51 [interquartile range 46–63] years of age; glycated hemoglobin A_1c (HbA_1c) 75 [68–88] mmol/mol [9.0% (8.4–10.4%)]; and urinary albumin-to-creatinine ratio (UACR) 89 [37–250] mg/g) were in a randomized controlled trial assigned to SAP therapy for 1 year. Anthropometrics, CGM data, and blood and urine samples were collected every 3 months. RESULTS Mean change (95% CI) in percentage of TIR (%TIR) was 13.2% (6.2; 20.2), in HbA_1c was-14.4 (-17.4;-10.5) mmol/mol (-1.3% [-1.6;-1.0]), and in UACR was-15% (-38; 17) (all P < 0.05). UACR decreased by 19% (10; 28) per 10% increase in %TIR (P = 0.04), 18% (1; 30) per 10 mmol/mol decrease in HbA_1c (P = 0.07), and 31% per 10-mmHg decrease in mean arterial pressure (P < 0.001). CONCLUSIONS In this longitudinal study, treatment-induced increase in %TIR was significantly associated with decrease in albuminuria in T1D.