Fe-Cr alloys with different Cr content were subjected to various heat treated conditions to produce σ phase. Micro-Vickers hardness and magnetic hysteresis loop (MHL) measurements were carried out at various heat treated conditions of the alloys to observe the change in mechanical and magnetic properties respectively. A drastic increase in hardness and coercivity whereas sudden drop in remanence and maximum induction were observed at large volume fraction of σ phase in higher Cr content alloy (48% Cr). At small volume fraction of σ phase no change in hardness was observed. However with the formation of small volume fraction of σ phase and its growth the magnetic properties change systematically. The study revealed that MHL technique would be a good Non-Destructive Evaluation (NDE) tool for the evaluation of σ phase in high temperature structural components made of Fe-Cr alloys.