Exposure to Ni, Cd or Al leads to different health issues depending on the dose and the exposure frequency. Their mechanism of action is poorly known, but as metals, they may have some points in common. The aim of this work was to compare the impact on cell bioenergetic of these metals using a common cell model: a normal human dermal fibroblast (NHDF) in primary culture. To study cell bioenergetics which ''concerns energy conservation and conversion processes in a living cell'' as defined by Demirel and Sandler, two technics are combined: oximetry and microcalorimetry. The heat flow measured by microcalorimetry reflects cell metabolism and more generally glucose catabolism (the only nutriment brought to the NHDF). Cell respiration is measured by oximetry and shows the impact on the mitochondria, the energy factory of the cell. Without incubation, Cd inhibits thermogenesis and cell respiration, Ni has no effect, and Al inhibits cell respiration but not thermogenesis. After 24 h of contact at 40 lM, NHDF died with Cd but seemed over-activated with Al and Ni (thermogenesis and cell respiration increased).