This paper examines how and why Samsung's semiconductor sector has grown very rapidly in light of the development of technological capabilities. After Samsung entered semiconductor industry in 1974, it successfully developed transistors and integrated circuits in the late 1970s. In 1982, Samsung's top management decided to make a large-scale investment in the advanced semiconductor business. Choosing DRAM as a major product, Samsung quickly followed up the leading semiconductor companies by successive developments of 64K, 256K, 1M, 4M DRAM in the 1980s. With the establishment of ULSI Research Institute in 1989, Samsung started challenging the new fronts there were not precedents at that time. Samsung developed 16M DRAM almost simultaneously with other leading companies, and 64M, 256M, 1G DRAM for the first time in the world. Samsung's rapid growth of technological capabilities in semiconductor sector was due to various factors including top management's leadership, appropriate choice of technological paths, unique technology development systems, and Korean government's semiconductor industry promotion policies.