We sought to determine the incidence and clinical spectrum of the paradoxical reaction (PR) to treatment in 1000 children with tuberculosis (TB). Its incidence was 3.3%, presenting as mediastinal adenopathy (n = 12), central nervous system (CNS) tuberculoma (n = 8), increasing size of lymph nodes (n = 8) and serositis (n = 5). Symptoms included breathlessness (n = 7, 21.2%), neck swellings (n = 5, 15.2%), hemiplegia (n = 3, 9.1%), raised intracranial tension (n = 2, 6.1%) and fever or diabetes insipidus (n = 1, 3% each). The mean age of onset of PR was 3.5 months after the start of anti-TB medication. PR was seen predominantly in boys. Mediastinal lymphadenopathy was more common in children aged <2 years. Tuberculomas were more common in children aged 2–5 years. Nodal enlargement and serositis were seen equally in all age groups.