Today, fibre-based materials are used in many applications. The fibre-reinforced composites are used as strong lightweight materials in many civil and constructional engineering applications. The fibrous porous scaffolds are used as supports for tissue growth in tissue engineering applications. The fibrous pads are used as absorbents in many medical and technical applications. In addition, there are a range of fibrous materials we use in our everyday life. The performance of these materials depends by and large on their structures and the characteristics of the fibres employed. The structure of the fibrous materials refers to the arrangement of fibres which is generally described by their directional arrangement and their packing arrangement. Properties of fibrous webs are usually determined by orientation of constituent fibers. Fiber orientation also can determine the anisotropic degree of webs or composite materials. Mechanical properties of nonwoven fabrics are expressed using properties of the components employed and also their structural arrangement within the web. In this respect factors such fiber morphology, fiber orientation, fiber crimp and fabric thickness are among the most important properties. Variation in these properties can affect the mechanical behavior as well as the fracture mechanisms of the fibrous structures. In order to change and improve the properties of the final product, these parameters can easily be made to vary during the production process. Permeability of anisotropic fibrous material is directly dependent on fiber orientation which in turn affects anisotropy of the fabric. Permeability is the property of a porous material that characterizes the traortation of a fluid through the material under a pressure gradient. In other words, it is the fluid conductivity of the porous material. The permeability characteristics of textile fabrics are dependent on pore shape and size, pressure drop and fibre and fabric geometries. Depending on the type of fabric (woven, knitted or nonwoven), the permeability influences other properties and various applications. Fibers are arranged in various directions in a nonwoven fabric. Mechanical properties such as strength, permeability, bending rigidity and phisycal properties like pore shapes and their distribution are controlled with fiber orientation of webs. Porosity of nonwoven has important role in determination of transfer properties such as heat and moisture transfer. The arrangement of fibers in the fabric can be influenced by both web formation and bond formation operations. Fibers can be arranged both two and three dimensionally. In the research the effect of fiber arrangement on mechanical and thermal transfer properties of fabrics have been studied. For this purpose samples were prepared and images of the cross-section of the samples were taken. Geometrical properties of the fabric cross sections were determine using image processing technique. Using this technique, it was possible to measure pore size and distribution of the samples. Additionally using the image processing technique, the mechanical properties of the samples were evaluated. Results showed that mechanical and thermal properties of the samples are directly affected by pore size and distribution. It was also found that ANN is a strong and valid tool for prediction of mechanical properties of the samples based on geometrical properties of the sample cross-sections. Key words : Fiber orientation, nonwoven fabric, ANN, image processing, porosity, pore distribution.