Abstract: Sickle Cell Anaemia (SCA) constitutes a factor in the health of mankind. One of the regulating agents concealed in the mortality factors of SCA sufferers is their level or quantity of Foetal Haemoglobin. This study proposes a function which relatively describes the chance of survival of SCA patients in respect to their Foetal Haemoglobin levels. It is observed that survival increases as the level of foetal haeoglobin increases, decreases as age increases and this depicts the real life scenario. These are shown graphically.