A study of fatigue cracking in iron-copper compacts was carried out to compare and analyse the performance of four different types of commercially used iron powders. The compacts were all sintered at above the iron copper peritectic temperature to facilitate liquid phase sintering. Results showed that the powder with a high specific surface had inferior fatigue properties, especially at high stress levels. The other powders, however, had very similar fatigue properties, except that at low stresses the grade with the large average particle diameter resulted in significantly longer fatigue lives. The differences in performance were discussed in terms of the microstructure of the compacts and the powder characteristics.