Human activity and natural processes have led to widespread dissemination of metals and metalloids, many of which are toxic and have a negative impact on agronomic production. Roots, as the first point of contact, are essential in endowing plants with tolerance to excess metal(loid) in the soil. The most important root responses include: adaptation of transport processes that affect uptake, efflux and long distance transport of metal(loid)s; metal(loid) detoxification within root cells via conjugation to thiol rich compounds and subsequent sequestration in the vacuole; plasticity in root architecture; the presence of bacteria and fungi in the rhizosphere that impact on metal(loid) bioavailability; the role of root exudates. In this review we will provide details on these processes and assess their relevance for the detoxification of arsenic, cadmium, mercury and zinc. Furthermore, we will assess if any of these methodologies has been tested in field conditions and whether they are effective in terms of improving crop metal(loid) tolerance.