The paper analyses the viability of health microinsurance in Brazil, through the calculation of premiums for various coverages. An original database was used with the microdata of an insurance company with 188,631 individuals. We used three criteria of choice of medical procedures: (a) frequency; (b) combined frequency and severity; and (c) elective and emergency consultations and low complexity examinations. The results indicate that the criterion (c) produced the lowest premiums, for all age groups. But this criterion only includes low complexity procedures and elective and emergency consultations. Some important high severity risks are not included, which can reduce the role of this type of microinsurance in reducing vulnerability and providing protection to low-income people.