Of the first 244 women admitted on Tuesday, most went into the army and air force with a few joining the navy.
They were previously allowed to serve only in medical units or musical bands.
The German authorities had resisted the move, but were forced to change their policy after a woman electronics operative, Tanja Kreil, took a case to the European Court of Justice and last January won the right to serve in fighting units alongside men.
Of the first 244 women admitted on Tuesday, most went into the army and air force with a few joining the navy.
Some 1,900 women have applied to join the German armed forces since the country's parliament voted in July to amend the constitution and the law governing the military, in line with the European Court ruling.
Sexual equality
The court in Luxembourg said the German ban on women bearing arms went against the European Union's principle of sexual equality.
A senior German military official, General Inspector Harald Kujat, told German NDR4 radio that the country's male soldiers "will make much more of an effort than they have in the past".
The army command centre in Koblenz said it would run special seminars for more than 200 officers to develop methods for preventing sexual harassment.
The defence ministry meanwhile predicts that the proportion of female soldiers will remain under 10%.
Germany had long opposed allowing women into its front-line combat forces. Even towards the end of World War II, as the Nazi leadership recruited elderly men and boys in a desperate effort to stop the Allied advance, women were not called up.
"One of the last gender-specific professional bans has been lifted," commented Rainer Bruederle of the liberal opposition Free Democrats.