An electromagnetic balance for the measurement of fluid density at low temperature and elevated pressure is described. The balance is operated by balancing the changes in gravitational forces due to the buoyancy of a sphere immersed in the fluid against the electromagnetic force between a current carrying coil and a permanent magnet. The apparatus, which requires a relatively small amount of fluid, is capable of high precision and can be operated at any temperature below ambient and at pressures up to 80 atm.