For an impact fracture test, the influence of Coulomb friction between the specimen and anvil on contact forces and dynamic stress intensity factor (DSIF) has been investigated numerically. It has been shown that friction leads to increasing of the mean tup and anvil forces and decreasing of mean DSIF. Additionally, in most cases, friction leads to increasing of the amplitude of DSIF oscillations and, in consequence, makes interpretation of the test results more complex. Simple formulae for correction of reduced by friction mean DSIF values have been proposed.