Time and stress-dependent viscoelastic properties of polypropylene fibers are determined by means of a series of creep tests and data analysis technique. Relaxation tests are carried out to verify and update the suggested model. The tests are performed for single polypropylene fibers that form a thermally bonded low-density nonwoven. The obtained properties are implemented into the finite element analysis software MSC. Marc - Mentat. Tensile tests and simulations are performed in order to demonstrate suitability of the developed creep model. The obtained results are discussed and further recommendations are given.