Acting on a tip off, the Directorate of Revenue Intelligence officials apprehended the duo when they alighted from a bus coming from Malda district of West Bengal last evening.
When they were searched, 908 gram of cobra venom was found in their possession, the officials said.
They have been identified as Birendra Mandal, resident of Madhepura district and Wakil Das, resident of Purnea district.
During interrogation, the duo said they were promised to be given Rs 2 lakh each after handing over the consignment to someone in Delhi, they said.