In this paper, fatigue life of a suspension lug for jointing a store to a special aircraft has been assessed. The lug is used for jointing a store (which is a fuel tank in this paper) to a training aircraft. Using the load factor exceedance data of this aircraft, the load spectrum of the lug in a flight envelope has been evaluated. Only the normal load factors has been considered for fatigue analysis, because the longitudinal load factor is small compared with the normal load factor, and the transverse load factor occurs only in maneuver phase. 10 times of each flight envelope has been considered as a loading block. Then using the rain-flow technique, Goodman criterion, Miner’s rule and the S-N curve of the materials, fatigue life of the lug has been predicted. The effect of selecting various materials for the lug on fatigue life has been evaluated. The results showed that using AISI 4340 steel – compared with other relevant materials in aeronautical structures – is more useful and gives suitable fatigue life. The fatigue lifetime of the lug prepared from AISI 4340 steel is 1250 flight hours and the inspection intervals for this specimen is 250 flight hours.