Background: Type 1 diabetes is associated with raised inflammation, impaired endothelial progenitor cell mobilisation and increased markers of vascular injury. Both acute and chronic exercise is known to influence these markers in non diabetic controls, but limited data exists in Type 1 diabetes. We assessed inflammation, vascular repair and injury at rest and after exercise in physically-fit males with and without Type 1 diabetes. Methods: Ten well-controlled type 1 diabetes (27 ± 2 years; BMI 24 ± 0.7 kg.m2; HbA1c 53.3 ± 2.4 mmol/mol) and nine non-diabetic control males (27 ± 1 years; BMI 23 ± 0.8 kg.m2) matched for age, BMI and fitness completed 45-min of running. Venous blood samples were collected 60-min before and 60-min after exercise, and again on the following morning. Blood samples were processed for TNF-α using ELISA, and circulating endothelial progenitor cells (cEPCs; CD45dimCD34+VEGFR2+) and endothelial cells (cECs; CD45dimCD133-CD34+CD144+) counts using flow-cytometry. Results: TNF-α concentrations were 4-fold higher at all-time points in Type 1 diabetes, when compared with control (P 0.05). Within the Type 1 diabetes group, the delta change in cEPCS from rest to the following morning was related to HbA1c (r = -0.65, P = 0.021) and TNF-α (r = 0.766, P = 0.005). Conclusions: Resting cEPCs and cECs in Type 1 diabetes patients with excellent HbA1c and high physical-fitness are comparable to healthy controls, despite eliciting 4-fold greater TNF-α. Furthermore, Type 1 diabetes patients appear to have a blunted post-exercise cEPCs response (vascular repair), whilst a biomarker of vascular injury (cECs) remained comparable to healthy controls.