Background: Recent research highlights the significance of short-chain fatty acids (SCFA), mainly derived from gut microbiota, in metabolic health. In individuals with type 1 diabetes (T1D), few data show an association between fecal SCFA and dietary fiber intake and a potential relationship with blood glucose control. Aims: To investigate the relationships between serum SCFA and blood glucose control and dietary habits in adults with T1D. Methods: In a cross-sectional study on 198 individuals with T1D (100M/98F), aged 18-79 years, serum acetate, propionate, butyrate, and total SCFA were analyzed by Gas-Chromatography/Flame Ionization Detector (GC/FID), blood glucose control was evaluated by glycated hemoglobin (HbA1c) and Continuous Glucose Monitoring (CGM) metrics, and diet was assessed by 7 days food record. Results: Hb1AC, serum acetate, and total SCFA levels significantly differed between women and men (p<0.05). Therefore, SCFA levels were categorized into sex-specific tertiles and adjusted for age and BMI. Hb1Ac, time in range (TIR), time above range (TAR), and time below range (TBR) did not significantly differ between tertiles of acetate and butyrate. Conversely, in women, the higher propionate tertiles demonstrated a higher percentage of TIR (p=0.013) and a lower percentage of TAR (p=0.009). In men, the high acetate tertile was associated with higher intakes of total dietary fat (p=0.041), PUFA (p=0.049), and MUFA (p=0.021). In women, the higher acetate tertile was linked to a lower intake of total dietary protein (p=0.002) and animal protein (p=0.001), the higher propionate tertiles were linked to lower fat intake (p=0.022), and the higher butyrate tertiles were linked to a lower carbohydrate intake (p=0.040). Conclusion: Our results highlight sex-specific associations of SCFA, especially propionate, with blood glucose control and dietary habits in people with T1D.