Precision Livestock Farming (PLF) is often perceived as an instrumentation of animals in order to make more profitable ‘industrial farms’. By contrast, one could argue that animal welfare can be better ensured if they are closely monitored with state of the art technology, enabling rapid feedback by the farmer. We will start from the main dimensions of animal welfare, as defined in the Welfare Quality® approach, to analyse how PLF can help to ensure the health and the comfort of animals, to promote appropriate behaviour, and to avoid distress. Examples will be mainly based from our own experience gained by the use of a Real Time Locating System that allows inferring the animal behaviour in real time. Not only the time a given animal spent in each activity or the distance it travels per day can help understanding whether this animal is functioning normally (e.g. spends sufficient amount of time resting or eating, or moves enough) but also the organisation of activities during the day or in relation to specific events (i.e. circadian rhythms, reactions to human approach) can give indications on subtle changes that reflect health or behavioural problems. We do not conclude that PLF is necessary for animal welfare nor that animal welfare is always promoted by PLF techniques but rather that including animal welfare considerations in the development and use of PLF techniques is essential to obtain profit for all: the farmer, the animal, and the society.