Autonomous loading implies a fully automated scenario in which automated excavating machines, such as front-loaders, load themselves from a heap of bulk material and deliver to the dumping site. The process comprises all the functions of loading, navigating, obstacle detection and avoidance and unloading to be automated and controlled by a supervisory computer. Autonomous loading benefits a number of industries such as construction and mining, from economical view point as well as other concerns like operators safety when the workplace is not hazard free. Despite all the benefits and despite considerable amount of research on the subject, there are no commercially available systems that can be purchased and put to work. In addition to a breakdown of all the tasks that need to be automated and the difficulties involved, this paper reviews and reports the various research and/or development activities that have been carried out during the past two decades on the subject.