Zn1-xFexO (x = 0.03,0.05,0.08,0.1) nanocrystals were synthesized from Zn nitrate and Fe nitrate reduced by citrate. The X-ray diffraction (XRD) shows that Zn1-xFexO (x <= 0.08) samples are single phase with the ZnO-like wurtzite structure, while the secondary phase ZnFe2O4 is observed in Zn0.9Fe0.1O sample. Magnetic measurements indicate that Zn1-xFexO (x = 0.03, 0.05, 0.08) are ferromagnetic at room temperature and appear exchange bias varies with Fe concentration. The origin of the ferromagnetic is given by exchange and Zn vacancies in samples. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.