Thermoplastic molding compositions comprising A) from 10 to 93% by weight of a thermoplastic polyester B) from 1 to 20% by weight of a phosphinic salt C) from 1 to 20% by weight of a nitrogen-containing flame retardant D) from 5 to 50% by weight of a long-fiber reinforcing material with fiber length from 2 to 25 mm and L/D ratio from 500 to 4000 E) from 0 to 50% by weight of other additives, where the total of the percentages by weight of components A) to E) is 100%.