This paper reports single-walled carbon nanotube-based biosensors for genetically modified organism (GMO) detection. Electrochemical electrode and single-walled carbon nanotube field effect transistor (SWCNT-FET)-based biosensors are used to determine the CaMV 35S promoter of Roundup Ready soybean. Given optimal conditions, both biosensors can effectively detect full complementarity with concentration as low as 1 nM. The sensitivity of the electrode-based biosensor is approximately 0.6 kU/nM while that of the SWCNT-FET-based biosensor is 0.32 nA/nM. Both biosensors were also used to determine a polymerase chain reaction-amplified sample. The obtained results showed that both sensors determined transgenic organisms well, thereby providing a useful tool for screening analysis of food samples. (C) 2015 Elsevier B.V. All rights reserved.