Plant 2S albumins are known as storage proteins present in seeds of some edible plants such as soybean, sunflower, mustard and Brazil nuts. These proteins have unusual secondary structure resulting from the presence of cysteine-rich motif C-Xn-CXn-CC-Xn-CXC-Xn-C-Xn-C and four disulphide bonds. Due to their structure, 2S albumins are stable to thermal processing and proteolysis. Some of the proteins have been identified as food allergens, but 2S albumins include also proteins of anti-inflammatory and antitumor activities. This review describes the properties and structures of the best characterized 2S albumins.