Allogeneic SCT was considered first-line CML therapy before 2000. The maturing positive experience with TKIs has now relegated its use to after first-line TKI failures. An impoant question is the optimal timing and sequence of TKIs and allogeneic SCT (whether allogeneic SCT should be used as second- or third-line therapy). Among patients who present with or evolve to blastic phase, combinations of chemotherapy and TKIs should be used to induce remission, followed by allogeneic SCT as soon as possible. The same applies to patients who evolve from chronic to accelerated phase. Patients with de novo accelerated-phase CML may do well with long-term TKI therapy (estimated 8-year survival rate 75%); the timing of allogeneic SCT depends on their optimal response to TKI (achievement of complete cytogenetic response). Among patients who relapse in chronic phase, the treatment sequence depends on several factors: (1) patient age and availability of appropriate donors; (2) risk of allogeneic SCT; (3) presence or absence of clonal evolution and mutations; (4) patient's prior history and comorbidities; and (5) patient and physician preferences Nowdays with the availability of effective TKI primary treatment modality for chronic and accelerated phase of CML is TKI therapy.If patient fails to respond to TKI then allogenic stem cell transplantation is the treatment of choice.so SCT is still the most effective treatment for accelerated and blast phase of CML Tyrosine kinase inhibitors are used as an interim therapy to achieve minimal CML burden. Interferons are given when allogeneic SCT is not feasible. Hydroxyurea, a ribonucleotide reductase inhibitor is used for controlling cell counts.