Alterations in TP53 have been described in many cancer types including hematological neoplasms. We aimed at comparing TP53 mutations (mut) and deletions (del) in a large cohort of patients with hematological malignancies (n=3307), including AML (n=858), MDS (n=943), ALL (n=358), CLL (n=1148). Overall, alterations in TP53 were detected in 332/3307 cases (10%). The highest frequency was observed in ALL (total: 19%; mut+del: 6%; mut only: 8%; del only: 5%) and AML (total: 13%; mut+del: 5%; mut only: 7%; del only: 1%), whereas TP53 alterations occurred less frequently in CLL (total: 8%) and MDS (total: 7%). TP53 mutations were significantly more frequent in patients ⩾60 vs <60 years in AML (9% vs 2%, P<0.001) and ALL (12% vs 6%, P<0.001). TP53mut+del had a significant negative impact on overall survival in all entities, whereas differences were observed regarding TP53mut only or TP53del only: TP53mut only impacted survival in AML (36 vs 9 months, P<0.001) and MDS (65 vs 19 months, P<0.001), TP53del only in CLL (not reached vs 64 months, P=0.008) and MDS (65 vs 24 months, P=0.011). As substantial differences between the entities are observed regarding correlation to age and survival, we suggest evaluation of both TP53 deletion and mutation status.