Filament yarns are yarns made of long, continuous fibers or strands that are twisted or combined. Filament fibers are much longer in length than staple fibers. Most filaments are mechanically or chemically processed from naturally extruded fibers or synthetic materials. They're squeezed out of a spinneret. Of all natural fibers, silk is a filament.

The properties of synthetic filaments can be changed as needed. Some of the characteristics of filament yarns are:
• The filament yarns have a smooth, uniform, and lustrous surface.

• Although the fabrics made from filament yarns have excellent strength but they have poor covering power.

Filament yarns are mainly classified into two categories:

• Monofilament yarn: Monofilament yarn is made from a single strand of filament fiber. Monofilament yarn is mainly used to make sewing thread, metal thread, bare elastic thread or fishing line.

• Multifilament yarns: Monofilament yarns are composed of two or more strands of long filament fibers twisted together. These types of filaments can be made from natural, non-synthetic and synthetic types of fibers. Multifilament yarns are mainly used for industrial purposes, rather than fabric or textile production.