Ultrasound-guided peripheral venous access (USG-PIVA) presents many advantages over the reference 'blind' technique in both adults and children in emergency situations. To compare USG-PIVA with the blind technique in children <3 years undergoing general anesthesia. After obtaining the approval of the ethics committee and informed consent from the parents, we included all children <3 years scheduled to undergo general anesthesia [surgery, magnetic resonance imaging (MRI)], who presented difficult venous access. The children were randomized into two groups: the US group (USG-PIVA) and the B group (blind). The primary endpoint was time to cannulation (from tourniquet placement to successful IV cannulation), compared between USG-PIVA group and B group by intention-to-treat analysis. Secondary outcomes were success rate at the first puncture, number of punctures, and diameter of the catheters. Cannulations requiring >15 min were considered as failures. In case of failure in group B, USG-PIVA was attempted for a further 15 min. Twenty children were included in each group. Groups were comparable for sex, age, and BMI. Significant differences were observed in median time to cannulation (63.5 s vs 420.5 s, USG-PIVA vs B respectively, P < 0.001); median number of punctures (1 vs 2.5, USG-PIVA vs B, P = 0.004); and success rate at first cannulation (85% vs 35%, USG-PIVA vs B, P = 0.0012). In contrast, overall success rate did not differ significantly between groups (90% vs 85%, USG-PIVA vs B, P = 0.63). Ultrasound-guided peripheral venous access leads to faster peripheral IV access and should therefore be recommended in children presenting with difficult venous access. © 2012 Blackwell Publishing Ltd.