Posterior reversible encephalopathy syndrome (PRES) is a gradually recognised neurological complication of allogenic haematopoietic stem cell transplantation (allo-HSCT). However, there is a paucity of information on PRES after haploidentical HSCT (haplo-HSCT). We performed a retrospective nested case-control study in patients following haplo-HSCT for malignant and nonmalignant haematologic diseases between January 2009 and December 2018 in our centre. A total of 45 patients were diagnosed with PRES after transplant, accounting for an incidence of 1.17%. Grades II to IV acute graft-versus-host disease (aGVHD) (HR 2.370, 95% CI 1.277-4.397, p = 0.006) and hypertension (HR 14.466, 95% CI 7.107-29.443, p < 0.001) were identified as risk factors for developing PRES after haplo-HSCT. There was no difference in overall survival (OS), disease-free survival (DFS), the cumulative incidence of relapse or nonrelapse mortality (NRM) between patients with PRES and controls without PRES following haplo-HSCT in either adults or children. All but one patient with PRES showed nearly complete clinical and neurologic recovery. In conclusion, PRES is a rare condition with benign outcomes following haplo-HSCT. Further multicentre prospective studies are needed to confirm the results and help to establish the standard therapy for posttransplant PRES.