Aims: Interventions on young horses may be particularly risky for professionals such as breeders or veterinarians, due to the young animals’ bad/non-existent education, often leading them to use constraint on the animals, thus increasing even more the risks. Here, we investigated the effects of using positive reinforcement (food reward) to train young horses to stand still and cooperate during handling, and we evaluated the effects of such training on the horse-human relationship. Methods: 23 yearlings were trained to remain immobile on a vocal order and accept various handling procedures (brushing, picking feet, surcingle, rectal thermometer ...), giving half of them a food reward (positive reinforcement group, NPR=11) whenever they responded correctly to the command (i.e. remained immobile throughout the handling procedure), while the other half (control group, NC=12) was never given any reward. Results: Results showed that using positive reinforcement promotes faster learning (P<0.001) and better memorization of the immobility task (P<0.05). Horses that received the food reward also behaved better during training (less biting, kicking..., P<0.05) than controls, and not only did they easily accept the tasks included in training, but also was it easier and safer to perform new tasks such as oral deworming or radiography, and at a later stage to perform saddle breaking (P<0.05). Moreover, rewarded animals sought and accepted more contact, both with the familiar trainer (P<0.001 and P<0.01, respectively) and with a non familiar person (P<0.01 and P<0.01, respectively), even several months after completion of training (at least 6 months later). Conclusions: This study reveals that the human-animal interactions that occur during horse training may be crucial to obtain a well-educated horse, as well as to establish a positive human-animal relationship.