Combination of CDF and D0 Results on the Mass of the Top Quark
  We summarize the top-quark mass measurements from the CDF and D0 experiments at Fermilab. We combine published Run-I (1992- 1996) measurements with the most recent preliminary Run-II (2001- present) measurements using up to 750/pb of data. Taking correlated uncertainties properly into account the resulting preliminary world average mass of the top quark is Mt=172.5 +/- 1.3(stat) +/- 1.9(syst) GeV/c2, which corresponds to a total uncertainty of 2.3 GeV/c2. The top-quark mass is now known with a precision of 1.3% - a 20% improvement relative to the previous combination. 
Tevatron Electroweak Working Group (for the CDF and D0 Collaborations)