Background: The current Canadian guidelines endorse the use of MgSO 4 for treatment of eclampsia and for prophylaxis in severe preeclampsia.Our study aimed to audit our institution's compliance regarding these guidelines. Methods:We conducted a retrospective study to evaluate MgSO 4 use in: all our cases of eclampsia since 2002, 50 cases of severe preeclampsia, and 50 cases of non-severe preeclampsia.Results: Sixty-five cases of preeclampsia were analyzed after initial chart review. A high rate of preeclampsia severity misdiagnosis was observed (35%, 23/65). Only 69% (25/36) of the patients correctly diagnosed with severe preeclampsia received MgSO 4 ; after diagnosis correction, 42% (25/59) of the patients with severe preeclampsia received the medication. Of our eight cases of eclampsia, none of the patients received MgSO 4 before the seizure (although three had clear indications). Conclusion:Given the importance of prophylactic MgSO 4 use in preventing eclampsia, we have implemented informative measures aimed at rapidly achieving complete compliance with the national guidelines.