The nucleocapsid (N) protein of Nipah virus (NiV) produced in a recombinant host can replace the use of inactivated virus as a diagnostic reagent because it is safer and affordable. The aim of this study was to express the N protein in Pichia pastoris. The N gene of NiV was cloned into the yeast expression vector, pPICZ B and expressed in P. pastoris. The recombinant N protein of NiV was purified using sucrose density gradient ultracentrifugation and was confirmed with Western blotting using rabbit anti-N antibody. The P. pastoris expressed N protein self-assembled into helical structures as large as 1.5 mu m as shown in an electron micrograph. ELISA analysis performed with the swine sera obtained during the viral outbreak proved that the recombinant N protein to be highly antigenic. The NiV N protein produced in P. pastoris serves as an alternative to the recombinant N protein produced in Escherichia coli. (C) 2011 Elsevier Ltd. All rights reserved.