Welding is a common joining process used extensively in automobile industries, aircraft machine frames structural work ship building and various other fields. The physical properties of these welds are influenced by several factors. In order to produce satisfactory weldments which fulfill the requirement of quality the integrity of quality control is important. To understand the various defects, their causes and remedies can help to ensure higher quality and longer lasting welds. This report contains essential information of surface irregularities and weld discontinuities. Non destructive testing (NDT) is a mechanism which helps in finding out of defects of any item like welds before major harms happen to the item without affecting its usefulness. This thesis discusses the non destructive testing of weld structures. There are more than fourteen methods of NDT in metals, in this thesis the most important ones Visual, Ultrasonic, X ray and penetrant testing are discussed in detail. The experimental results are discussed and comparisons are made based on cost, accuracy, safety, time consumption, etc. Based on these comparisons conclusions and recommendations are made.