Objective[|]Although breath-holding spells (BHS) are the most common form of non epileptic paroxysmal events in infancy, the pathophysiology of these events remain unknown. Several studies have indicated that multiple factors can be involved in the pathogenesis of BHS. The aim of this study was to assess the associations between BHS and serum magnesium and calcium levels.[¤]Materials and Methods[|]This prospective, case-control study enrolled 79 consecutive children with BHS and 114 healthy children, who were included as controls, without any illness between October 2012 and January 2014. Mean hemoglobin (Hb), mean corpuscular volume, serum iron, serum iron binding protein, magnesium(Mg), calcium(Ca), phosphorus (P), and alkaline phosphatase levels and Ca/Mg ratiowere compared between the two groups.[¤]Results[|]Overall, the Hb, Ca, and P levels were in the normal range in both groups; however, the mean Hb, Ca, and P levels were significantly lower in the BHS group than in the control group. Furthermore, there was no significant difference in the mean serum Mg level or Ca/Mg ratio between the groups.[¤]Conclusion[|]Therefore, low Hb, Ca, and P levels may decrease the threshold of BHS and thus constitute a risk factor for the development of BHS.[¤]