OBJECTIVE: To draw attention to complications that might arise in any Kawasaki disease (KD) stage, risk factors contributing to the onset of complications and possible transient or permanent disease sequelae. METHODS: Prospective study (clinical cohort) conducted between April 2002 and April 2009 of 115 patients with KD admitted to the Pediatric Rheumatology Clinic of the General Hospital of the Federal District, Brazil. All patients were sequentially assessed with clinical and laboratory examinations, Doppler echocardiography, imitanciometry, auditory evoked potentials, psychological evaluation, ophthalmologic examination and, in one patient with chorea, cerebral magnetic resonance angiography. In all patients, a questionnaire assessing the possible presence of cognitive, emotional, behavioral and social disorders was applied. RESULTS: Twenty-five patients (21.7%) had coronary aneurisms. Thirty eight patients (33%) had a sensorineural auditory loss during the acute and subacute phases of the disease and 13 patients (11.3%) maintained the auditory loss six months after the first assessment. Other complications observed were as follows: facial palsy in one patient (0.9%), ataxia in acute and subacute phases in 11 (9.5%); 15 patients had ophthalmologic complications (13.2%), with uveitis in 13, papilledema in one patient, and conjunctival hemorrhage in another patient. One patient experienced chorea (0.9%), with a magnetic resonance angiography showing changes consistent with cerebral ischemia. In one patient, a thoracic aorta aneurism was found (0.9%) and another patient had a necrotizing vasculitis progressing to peripheral gangrene and tongue tip loss (0.9%). Behavioral changes over convalescence were observed in 23 children. CONCLUSION: KD may progress with several complications even within months of the disease acute phase, eventually resulting in permanent sequelae. The earlier the diagnosis and therapeutic intervention with IV IgG administration are, the lower will be the occurrence of complications; the presence of thrombocytosis, anemia and elevated and extended inflammatory activity are risk factors for complication arising.