The aim of this analysis was to examine sex-based differences in renal segmental resistances in healthy controls (HC) and patients with type 1 diabetes (T1D). We hypothesized that hyperfiltration - an early hemodynamic abnormality associated with diabetic nephropathy (DN) - would disproportionately affect women with T1D, thereby attenuating protection against the development of renal complications. Glomerular hemodynamic parameters were evaluated in HC (n=30) and in normotensive, normoalbuminuric patients with T1D and either baseline normofiltration (n=36, T1D-N, glomerular filtration rate [GFR] 90-134 ml/min/1.73m2) or hyperfiltration (n=32, T1D-H, GFR≥135 ml/min/1.73m2) during euglycemic conditions (4-6 mmol/L). Gomez's equations were used to derive efferent (RE) and afferent (RA) arteriolar resistances, glomerular hydrostatic pressure (PGLO) from inulin (GFR) and paraaminohippurate (effective renal plasma flow - ERPF) clearances, plasma protein and estimated ultrafiltration coefficients (KFG). Female TID-H had higher RE (1985±487 vs. 1381±296 dyne•sec•cm-5, p<0.001) and filtration fraction (FF, 0.20±0.047 vs. 0.16±0.03 p<0.05) and lower ERPF (876±245 vs. 1111±298 ml/min/1.73m2 p<0.05) compared to male T1D-H patients. Overall, T1D-H patients had higher PGLO and lower RA vs. HC subjects, although there were no sex-based differences. In conclusion, female T1D-H patients had higher RE and FF and lower ERPF than their male counterparts with no associated sex differences in RA. Prospective intervention studies should consider sex as a modifier of renal hemodynamic responses to renal protective therapies.