G6PD deficiency is a hereditary genetic disease that can cause haemolytic anaemia resulting from severe haemolysis in case of oxidative stress. It is a generally asymptomatic pathology and not well-known in Algerian society. For this reason, we conducted a descriptive study on 46 cases (patients) in a medical analysis laboratory of Oran, Algeria. Our results revealed a clear male predominance with 69.6% of cases, whose most affected age group was from 11 to 20 years. Haematological data clearly showed a reduction in red blood cell Hb levels due to the severe haemolytic crisis. The erythrocyte G6PD enzyme assay was low in 39.13% of patients, who in turn marked an indirect bilirubin level higher than the direct bilirubin level with 66.7%. G6PD deficiency is not a critical disease, but it must be diagnosed early if the symptoms are present in order to prevent the disease worsening. The molecular biology techniques make it possible to detect the mutations present in the G6PD gene, which make it possible to confirm the diagnosis of G6PD deficiency, when a patient presents indicative symptoms. These tests provide therefore information about the individual’s health and their families