Background: In population-based studies, patients presenting with minor or mild stroke symptoms represent about two-thirds of stroke patients, and almost one-third of these patients are unable to ambulate independently at the time of discharge. Although mechanical thrombectomy (MT) has become the standard of care for acute ischaemic stroke with proximal large vessel occlusion (LVO) in the anterior circulation, the management of patients harbouring proximal occlusion and minor-to-mild stroke symptoms has not yet been determined by recent trials. The purpose of this study was to evaluate the impact of reperfusion on clinical outcome in low National Institutes of Health Stroke Scale (NIHSS) patients treated with MT. Methods: We analysed 138 consecutive patients with acute LVO of the anterior circulation (middle cerebral artery M1 or M2 segment, internal carotid artery or tandem occlusion) with NIHSS <8, having undergone MT in 3 different centres. Reperfusion was graded using the modified thrombolysis in cerebral infarction (TICI) score and 3 grades were defined, ranging from failed or poor reperfusion (TICI 0, 1, 2A) to complete reperfusion (TICI 3). The primary clinical endpoint was an excellent outcome defined as a modified Rankin score (mRs) 0-1 at 3-months. The impact of reperfusion grade was assessed in univariate and multivariate analyses. The secondary endpoints included favourable functional outcome (90-day mRS 0-2), death and safety concerns. Results: Successful reperfusion was achieved in 81.2% of patients (TICI 2B, n = 47; TICI 3, n = 65). Excellent outcome (mRs 0-1) was achieved in 69 patients (65.0%) and favourable outcome (mRs ≤2) in 108 (78.3%). Death occurred in 7 (5.1%). Excellent outcome increased with reperfusion grades, with a rate of 34.6% in patients with failed/poor reperfusion, 61.7% in patients with TICI 2B reperfusion, and 78.5% in patients with TICI 3 reperfusion (p < 0.001). In multivariate analysis adjusted for patient characteristics associated with excellent outcome, the reperfusion grade remained significantly associated with an increase in excellent outcome; the OR (95% CI) was 3.09 (1.06-9.03) for TICI 2B and 6.66 (2.27-19.48) for TICI 3, using the failed/poor reperfusion grade as reference. Similar results were found regarding favourable outcome (90-day mRs 0-2) or overall mRS distribution (shift analysis). Conclusion: Successful reperfusion is strongly associated with better functional outcome among patients with proximal LVO in the anterior circulation and minor-to-mild stroke symptoms. Randomized controlled studies are mandatory to assess the benefit of MT compared with optimal medical management in this subset of patients.