New fiber‐forming polyamides containing heterocyclic groups were prepared form furan 2,5‐dipropionic acid and the corresponding tetrahydrofuran compound which were found to be prepared easily from furfural and levulinic acid. For example, poly‐decamethylenetetrahydrofuran 2,5‐dipropionamide (intrinsic viscosity 0.74) gave a fiber having, when cold drawn to 350%, tensile strength 3.1 g./denier and elongation 25%.