Sickle cell anaemia (SCA) constitutes a serious public health problem in sub-Saharan Africa and a common cause of childhood morbidity and mortality. Foetal haemoglobin (HbF) is one of the modifiers of sickle cell severity, and it retards polymerization of sickled haemoglobin (Hb) in sickle cell anaemia in the deoxygenated state. Studies have shown that the levels of HbF vary among patients and regions and that its level may correlate with disease severity, while some other studies did not establish this relationship. In Nigeria, studies on the levels of HbF and its relationship with haematological indices and disease severity are limited, this study was conceived and carried out. This study was a cross-sectional, descriptive, and hospitalbased, whose objectives were to estimate HbF levels of children with SCA in Lokoja, North central, Nigeria. and to correlate the levels of HbF with some haematological indices (TWBC, Platelet, PCV, HB, MCV, MCHC, MCH, RDW) and disease severity.