The surface tension of He3 has been measured by a capillary rise method between 1.08° and 2.32°K. A decrease of more than 50% was observed in this range and this supports the ideas on which Atkins' theory of the surface tension of liquid helium is based. On the basis of this theory the surface tension has been extrapolated to 0°K., where it has the value 0.154 ± 0.005 erg cm.−2. Above 2.3°K. it was extrapolated linearly to zero at the critical temperature. The Eötvös constant was calculated to be about 0.8.