Germination is one of the main stages of a plant's life cycle. Since seed hydration by imbibition is a prerequisite for germination, seed priming techniques provide not only water that is absolutely necessary for the initiation of processes related to strict germination, but also additional physiologically effects due to the qualitative and quantitative composition of the solution used. The objectives of this study were to evaluate the effects of some priming treatments (Hidropriming, ASFAC and Diatomaceous earth) on seeds germination and vigour of tomato ( Lycopersicon esculentum Mill.) seedlings. The effects of treatments have been differentiated in terms of germination process characteristics and / or early seedlings growth, in close interdependence with the concentration of the substance used and especially in relation with the effects of their chemical nature on physiological and biochemical processes. Tomato seeds priming with ASFAC 0.5% assures some benefits on germination efficiency and early seedling vigour. Priming with diatomite may improve seedling growth, in a concentration dependent manner. We appreciate the need to further studies to investigate more varieties, more treatments times and a wider range of concentrations.