The aim of the study was to determine the nature, severity, precipitants and associated features of attacks and the incidence of potential aetiological factors of cyclic vomiting syndrome (CVS). Ten patients (6 boys and 4 girls aged 2-12 years) with CVS, defined as recurrent episodes of vomiting with symptom-free intervals occurring two or more times per year, with episodes having a similar pattern and for which no other cause could be found, ten patients (7 boys and 3 girls aged 7-14 years) with migraine, defined as recurrent headache with symptom-free intervals and at least three of the following symptoms or associated findings: abdominal pain, nausea or vomiting, throbbing headache, unilateral location, associated aura (visual, sensory, motor), relief after sleeping and ten controls (6 boys and 4 girls aged 4-13 years) were studied. The mean age at onset of symptoms in patients with CVS was 3.9 years and the mean number of attacks per year was 4, the average duration of episodes was 20.5 hours and the mean number of school missed days were 6 per year. The mean age at onset of symptoms in patients with migraine was 7.6 years and the mean number of attacks per year was 9.9, the average duration of episodes was 8 hours and the mean number of school missed days were 6.4 per year. A family history of migraine was significantly higher in both groups of patients, compared with controls (p = 0.009). A personal history of headache and/or migraine and associated sign or symptoms like recurrent abdominal pains, limb pain and kinetosis was significantly higher in both patients compared with controls (p < 0.001). CVS is a chronic, disabling condition and is a migraine variant, with attacks usually precipitated by stress and intercurrent infections.