In recent years, there has been renewed interest in the role of non-metallic inclusions in controlling the microstructure of steels. The potency of various inclusions and precipitates such as SiO 2, MnO·SiO 2, MnS, Al 2O 3, Ti 2O 3 and VN for the nucleation of intragranular ferrite has been examined in the present study. Among them, single SiO 2, MnO·SiO 2, Al 2O 3, TiN and MnS particles seem to be inert to the nucleation of intragranular ferrite under the present experimental condition. Ti 2O 3 particles in a Mn-containing steel are very effective for the nucleation of intragranular ferrite, being (Ti,Mn) 2O 3 particles by absorbing Mn atoms from a steel matrix. On the other hand, Ti 2O 3 particles in a Mn-free steel are not effective. MnS and Al 2O 3 particles in high nitrogen steels containing vanadium also appear to be potent for the nucleation of intragranular ferrite. The decrease in transformation temperature causes a change in the morphology of intragranular ferrite from idiomorphic ferrite to acicular ferrite.