Sickle cell disease (SCD) complications are associated with oxidative stress. Glutathione S-transferases (GSTs) are a group of enzymes that protect against oxidative stress. The aims of this study was to evaluate the prevalence of GSTM1, GSTT1, and GSTP1 gene polymorphisms among homozygous sickle cell anemia patients and to investigate the possible association between the presence of these polymorphisms and SCD severity and complications. Genotyping the polymorphisms in GSTT1 and GSTM1 genes was performed using the multiplex polymerase chain reaction (PCR) method. The GSTP1 ILe105Val polymorphism was determined using PCR–restriction fragment length polymorphism. GSTM1 null genotype was significantly associated with increased risk of severe vaso-occlusive crises (VOC) (odds ratio = 1.52, 95% confidence interval = 0.42–5.56, P = 0.005). We found no significant association between GST genotypes and frequency of sickle cell–related pain, transfusion frequency, disease severity, or hydroxyurea treatment. GSTM1 gene polymorphism may be associated with risk of severe VOC among Egyptian SCD patients.