The mechanism of breath-holding spells (BHS) is not fully understood and most probably multifactorial; so, this study was designed to clarify the pathophysiology of BHS through assessing some laboratory parameters and electrocardiographic (ECG) changes which might be contributing to the occurrence of the attacks. Another aim of the study was to evaluate the differences in the pathophysiology between pallid and cyanotic types of BHS. This was a prospective study performed in Zagazig University Hospitals. Seventy-six children diagnosed with BHS were included as follows: 32 children with cyanotic BHS, 14 children with pallid BHS, and 30 healthy children as a control group. All children were subjected to the following: full history taking, clinical examination, and laboratory work up in the form of CBC, serum iron, ferritin, and zinc levels. Twenty-four hours ambulatory ECG (Holter) recording was also performed. No significant statistical difference was found between cyanotic and pallid groups regarding family history of BHS, severity, and precipitating factors of the attacks. Frequent runs of respiratory sinus arrhythmia (RSA) during 24 hours ECG were significantly higher in children with BHS; the frequency of RSA was significantly correlated with the frequency (severity) of the attacks. Low serum ferritin was significantly associated with BHS groups but not correlated with the severity of the attacks. Autonomic dysregulation evidenced by frequent RSA is considered to be an important cause of BHS in children and is correlated with the frequency of the attacks. Low serum ferritin is additional factor in the pathophysiology. Both pallid and cyanotic BHS are suggested to be types of the same disease sharing the same pathophysiology.