We describe ten cases of tetanus in the newborn and nineteen cases of no umbilical tetanus, treated by diazepam, as the only muscle relaxant and tranquillizer medicine. There were seven deaths among the first ones (70%) and four among the last ones (21,1%). The former experiment of the Service showed a mortality of 90% for the cases of umbilical tetanus and 25,2% for the others. Although the difference between the two groups cannot be considered significant, we are forced to conclude that: 1st: - The muscle relaxant and tranquilizer action of diazepam showed to be in these observations, at least equal and probably superior than the other drugs so far used isolately or in association, in our Service; 2nd: - Its administration by the veint the most efficient, is of easy accomplishment. We did not notice in any of our cases, in spite of the periods of usage of diazepam, any case of thrombophlebitis; 3rd: - Although many times the doses given have been frequently high, the collateral manifestations due to the drug were of very little importance; 4th: - In none of the fatal cases we can blame the drug for that.