The objectives of this paper are to examine (1) the association between flexible employment and nurses' intention to leave the profession, and (2) whether or not support at work mediates the association between flexible employment and nurses' intention to leave the profession. Flexible employment is analyzed objectively using non-permanent contract, part-time employment status, casual employment status, involuntary hours and on-call work, and subjectively using job insecurity. Support at work refers to organizational, supervisor and peer support. Data come from our survey of 1396 nurses employed in three teaching hospitals in Southern Ontario. Descriptive statistics are provided. Bivariate correlations, hierarchical regression analysis and mediation tests are conducted. Compared to those in full-time employment, nurses in part-time employment do not intend to leave the profession. None of the other objective flexible employment factors are associated with intention to leave the profession. Perceived job insecurity is associated with intention to leave the profession. Low support at work contributes to intention to leave the profession and mediates the association between job insecurity and intention to leave the profession. The study provides evidence to health sector managers and policy makers that part-time employment, perceived job security and support at work are important factors to consider in efforts to retain nurses in the profession. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.