Geosynthetics industry is nothing short of excitement during the past three decades or so. Geosynthetics are now widely used on geotechnical, environmental, transportation, hydraulics, and other areas. The success can be largely attributed to the development of geosynthetic testing and specification and their standardization, which provide necessary material parameters and guidelines for the design and construction. Aside with this success, numerous failures were observed with geosynthetics and geosynthetics-related structures during the development course as well. A large number of these failures are associated with inappropriate use of material properties, the disagreement between practice and specifications, or lack/ignorance of material testing and specifications. This paper will discuss both the development and importance of testing and specification on geosynthetics.