9 years old male child presented clinically with thalassaemia intermedia phenotype. Investigations revealed hemolytic anaemia due to an unstable hemoglobin. Parents were found negative for the abnormal hemoglobin, suggesting a spontaneous mutation in the child. This is the third case of unstable hemoglobin to be reported from India. Clinically it is important that unstable hemoglobin should be suspected in a patient with thalassaemia intermedia phenotype even if both parents are haematologically normal.