Of the cancelled flights, 23 were inter-continental services, Lufthansa said in a statement.
The flight attendants' union UFO initial stoppage began at 1300 GMT today and affected flights to and from the airports of Frankfurt and Duesseldorf.
The union also announced a second, much-longer walkout tomorrow to turn the heat up on management.
Tomorrow's stoppage would also hit Frankfurt and Duesseldorf and would begin at 0500 GMT and last until 2200 GMT, UFO said.
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The group's subsidiaries Germanwings, Eurowings, Lufthansa CityLine, SWISS, Austrian Airlines, Air Dolomiti and Brussels Airlines are not being targeted by the industrial action.
Lufthansa said it "regretted" the union's action and apologised to passengers, saying the short notice of the strikes made it difficult to inform them in time and enable them to make alternative travel arrangements.
"We will do everything possible to keep disruption to a minimum," it said.
UFO plans to stagger the walkouts and target different airports over the course of the next seven days, with a repeat of the stoppages planned in Frankfurt and Duesseldorf tomrrow.
In addition, "no industrial action is planned at all on Sunday since most people travelling that day will be doing so in a private capacity," UFO said.
UFO had announced on Thursday that industrial action was "unavoidable" after management had failed to come up with an improved offer in a long-running dispute over pay and early retirement provisions.
Lufthansa said it has provisionally booked 2,500 hotel rooms in and around Frankfurt for passengers grounded by the strikes.
The UFO union said it would give sufficient advance warning of when the strikes will take place.
It is first time that cabin staff have staged walkouts in the nearly two-year-long dispute.