With a fully automated high temperature calorimeter the enthalpy of formation of the [Rh-Ga] liquid system was determined between 960<T e /K<1649, on the molar fraction range 0<x<0.53 (with x=x R h ). The molar enthalpy of formation of the [Rh-Ga] liquid alloys [Δ m i x H m o ] corresponding to the reaction, at T e and p o :aGa ( l i q ) +bRh ( l i q ) ->Ga x Rh ( 1 - x ) ( l i q ) can be described by the following Redlich-Kister equation (in kJmol - 1 )Δ m i x H m o =x(1-x)ξ(y)withξ(y)=-254.70-2.38y+86.07y 2 -22.76y 3 andy=x R h -x G a .This function is negative with an estimated minimum Δ m i x H m o =-64+/-4 kJmol - 1 at x=0.50, and independent of temperature, within the experimental error. The limiting partial molar enthalpy of mixing of rhodium, deduced from experiments performed at 1154 K and 1486 K, is:Δ m i x h m o (Rhsupercooledliquidin~liqGa)=-143+/-5kJmol - 1 .On the other hand, by extrapolation of the ξ-function to x=1, the limiting enthalpy of Ga in supercooled liquid Rh was predicted with a larger uncertainty:Δ m i x h m o (Galiq.in~supercooledliquidRh)=-194+/-30kJmol - 1 .T he enthalpy of formation of the solid RhGa 3 compound at 298 K was determined by dissolution calorimetry :Δ f o r m H m o (Rh 0 . 2 5 Ga 0 . 7 5 ;298K,sol)=-80kJmol - 1 .From these calorimetric experiments, some points of the equilibrium phase diagram were obtained; thus the first shape of the liquidus of the [Rh-Ga] system (in the Ga-rich region) has been proposed. The integral and limiting partial enthalpies of mixing have been compared with (i) the predicted Miedema et al. values, (ii) with the data previously obtained for the (TM-Ga) systems. Moreover a transfer of electrons from gallium towards rhodium is suggested by the strong enthalpy of formation of the [Rh-Ga] liquid system.