Background and aims: Vaso-occlusive crisis (VOC) is one of the hallmark of sickle cell disease (SCD). It is defined as a multicellular adherence causing a painful vase-occlusion, driving the acute and chronic pain associated with the disease, as well as the complication by end-organ damage. In Brazil, it is estimated that about 30% of SCD patients have at least three VOCs per year. This study aims to determine VOC prevalence among SCD patients in Brazil, as well as to estimate the frequency of crises in a 12-month period. Material and methods: Data were obtained through a multi-country (16 countries) survey of unmatched SCD patients and HCPs developed by international SCD experts, patient advocacy groups and Novartis (The SWAY Survey). The subjects were invited to participate via their healthcare professional or patient association groups. All patients with the diagnosis of SCD were eligible for inclusion and those aged 6 to 11 years old completed the questionnaire with a caregiver/parent/legal guardian. VOC characteristics, such as mean number of crises and management strategies in the previous 12-month period before survey, were assessed. Patients were also asked to classify which level of pain would cause them to use strong analgesics (such as opiates), to seek the assistance of a medical professional, to miss work/school and to miss important social events in a scale ranging from 0 (not severe al all) to 10 (worst imaginable). Descriptive analyses and chi-square tests were performed. Results: A total of 260 Brazilian patients of all genotypes (self-reported) with diagnosis SCD were included, most of them female (58.5%; n=152) with a mean age of 23.1 (SD: 14.0) years. The prevalence of at least one VOC in the previous year was 87.7% (n=228) for total sample, 88.3% (n=98) among those aged 6-16 years old and 87.2% (n=130) among those >16 years. Patients had a mean of 4.0 (SD=4.6) crises, 12.3% (n=32) had only one episode, 44.6% (n=116) 2-4, 25.4% (n=66) 5-10 and 5.4% (n=14) ≥11 episodes. A similar percentage distribution was observed when the subjects was stratified by age. No difference in the frequency and distribution of VOC was observed in patient with or without HU (HU 87.6% vs without HU 87.9%; p=1.000) and the categories of frequency of episodes during the year (p=0.799). Considering crisis management, 32.3% (n=84) reported to deal with it at home, most frequently due to reasons such as a poor experience at the emergency room or hospital (n=41; 48.8%). The patients with the worst imaginable level of pain (a pain score of 10) led patients to use analgesics, to seek for assistance, to miss work/school and social events for 24.9%, 24.1%, 23.1% and 21.3% of patients, respectively. Discussion: Almost all patients experience at least one VOC in a 12-month period, regardless the age and HU use. Furthermore, the frequency of crisis may be greater than five for about 30% of patients in all age groups. Data is consistent with those previously reported and reinforces the importance of VOC on SCD management. Conclusion: The vast majority of Brazilian SCD patients reported at least one episode of VOC in a 12-month period, regardless of age. Thus, VOC is still an important issue for Brazilian SCD patients and interventions able to decrease its occurrence are still needed.