The objective of this study is to reduce the morbidity of children with homozygous sickle cell disease presenting severe forms. We have conducted a longitudinal study between November 2015 and September 2017 at the Brazzaville University Hospital. Children with sickle cell disease requiring treatment with hydroxyurea were included. The variables studied were therapeutic compliance, evolutive profile of nutritional status, indications of hydroxyurea, electrophoresis of hemoglobin, blood count, and toxicity. The statistical test used was Student test with a significance threshold of less than 0.05. One thousand twenty-four children were monitored for sickle cell disease, 107 of which had received hydroxyurea (10.4%). The indications for hydroxyurea were recurrent anemic attacks (≥ 4) in 62 cases (57.9%), neurological crises 19 cases (17.8%), recurrent hyperalgesic crises in 17 cases (15.9%), priapism in 4 cases (3.7), and acute thoracic syndrome in 2 cases (1.9%). Therapeutic compliance was good in 89.5% of them. A rapid and lasting clinical improvement was noted in the majority of patients with hyperalgesic attacks (88.2%) and anemic attacks (88.7%), two recurrences for the cerebrovascular accidents, and an absence of recurrence of priapism and of the acute thoracic syndrome. From the biological point of view, there was a significant increase in fetal hemoglobin (1.2 to 16.2%; P  < 0.05), hemoglobin (7 to 8.3 g/dl; P < 0.05), mean cell volume (80.8 to 96 fl; P  < 0.05) and a significant decrease in mean white blood cell count (15,633 to 9,872/mm3; P  < 0.05) and platelets (387,002 to 324,400/mm3; P  < 0.05). The signs of toxicity observed were mainly vomiting and thrombocytopenia in two cases each, one case with headache and the other with neutropenia. Indications for use of hydroxyurea therapy in children with sickle cell disease in Brazzaville are common. These are dominated by recurrent anemic seizures, strokes, and hyperalgesic seizures. The excellent evolution of these complications under hydroxyurea represents an interesting alternative in our countries with limited resources.