The carpet pile and the carpet base can either be a natural or a synthetic material or it can a be a combination of the synthetic and natural substances.
The base of the carpet and the carpet pile can be manufactured from different material in the same carpet. The selection of material is based on a number of factors: ease of manufacture, durability, appearance and the cost.
Carpet construction and the carpet fiber material determine the life of the carpet and how it will sustain the usage. Denser the fiber, better the life of a carpet. Fiber density and the quality of the fiber are the prime factors involved in deciding the cost of the carpet.

Amongst the natural substances, wool is the most commonly used material. Wool is mostly used in rugs. Silk, jute are also used in some cases. But their usage is comparatively limited and specific to only certain countries and areas.
Commonly used synthetic materials are nylon, polypropylene, polyester and acrylic.
In the present day scenario, synthetic material is used extensively in manufacture of carpets and comprise an estimated 95% to 97% of the carpet industry.

Material used for manufacturing the fiber is drawn into yarns and the single fibers are then spun together to create two or three four-ply yarns, which are then attached to a woven backing, the base of the carpet or the rug.

Wool
Wool has been a natural choice for centuries in the creation of carpets. It still remains a favorite, but mostly in cases of rugs. Wool offers a deep, rich look and gives a luxurious look to the room. Wool offers excellent resilience and durability. It is moderately stain resistant, but, requires a high level of maintenance and is costlier than the synthetic materials. The inherent characteristics of wool to scatter light results in lesser visibility of carpet stains.
Wool is now-a-days blended with synthetic material to give a better durability to the carpet while maintaining the look and to some extent the feel of the carpet. In modern day carpets, blended woolen yarns are used quite extensively.

Nylon
The most commonly used material in production of carpets. Nylon is the strongest of the fibers making it a natural choice in high-traffic areas. It is durable and easy to clean. Nylon can be dyed with a wide range of colors, can be printed in any colors and made into various styles and textures, making it a highly favorable material for both the carpet manufacturers as well as buyers.
On the down side, some nylon carpets may generate static.

Polypropylene
Polypropylene or Olefin carpets originally were manufactured for outdoor purposes. These carpets have a better resistance to moisture, water, dew and shedding. It has a wool like feel and appearance. This along with the better resistance has prompted manufactures to use it for indoor carpets too. Polypropylene fibers are dyed before being converted to yarns and hence do not fade easily.

Polyester
Used in mid to low price carpeting, polyester carpets are stain resistant and competitively priced. They are not as durable as Wool or nylon carpets. Available in a wide variety of colors, polyester carpets may pill and shed.

Acrylic
Acrylic fibers are soil resitant and resistant to dew. They are closest to wool and are available in a wide range of colors. They also fade less in bright sunlight than their nylon or polyester counterparts.