Using a neutron interferometer the bound coherent neutron-tritium scattering length was determined to b,. = 5.10 _+ 0.10 fm. This yields a free scattering length of ac=3.82 _+0.07fm. Together with the recently measured free cross section (c% =1.70 _+ 0.03 b [5, 6]) new recommended values for the singlet and triplet scattering lengths are obtained (a~=3.70+0.62 fm, at=3.70+_0.21 fm). These values are compared with theoretical estimates based on recent calculations for the four nucleon systems.