The four-month-old child died while being treated for suspected measles.
According to the Sylhet Divisional Health Office, the total number of suspected and confirmed measles deaths in the division has now reached 139 this year.
Currently, 337 patients with measles symptoms are admitted to hospitals across the division.
Health officials say 49 people have died in Sylhet, 14 in Habiganj, 12 in Moulvibazar and 54 in Sunamganj from suspected measles.
Six more deaths from confirmed measles have also been reported across the division.
