METHODS Registry study using prospectively collected data Objective:  To determine risk factors for cardiac complications in spine surgery. METHODS The Spine End RESULTS Registry 2003-2004 is an exhaustive database of 1,592 patients who underwent spine surgery at the University of Washington Medical Center or Harborview Medical Center. Detailed information regarding patient demographic, medical comorbidity, surgical invasiveness and adverse outcomes were prospectively recorded. The primary outcome of measure was the occurrence of a cardiac complication in the perioperative period. Relative risk (RR) and 95% confidence intervals were calculated for each of the categorical variables. Multiple log-binomial regression analysis was performed to investigate the independent factors associated with cardiac complication. RESULTS The incidence of cardiac complication after spine surgery was 6.7%. There were 136 cardiac complications in 107 patients after spine surgery. Age, diabetes, previous cardiac history, elevated adjusted Charlson comorbidity score, revision surgery, combined anterior-posterior approaches, and surgical invasiveness were statistically significant risk factors for cardiac complication after spine surgery. CONCLUSIONS The results of the present study suggest numerous statistically significant risk factors for cardiac complications after spine surgery. These results may aid the clinician with preoperative risk stratification and patient counseling. [Table: see text] The definiton of the different classes of evidence is available on page 73.