Acoustic emission (AE) technique was applied to evaluate both tensile deformation of 316L stainless steel and bending-fatigue damage of socket-welded pipe. AE activity was monitored during tensile deformation of plate-type specimens subjected to various heat treatments. Variation in RMS voltage of AE signal was correlated with the amount of strain-induced martensite phase. Secondly, actual size of socket-welded pipe specimen was bending-fatigued under various stresses. Crack initiation was determined by observing an abrupt increase in AE count, and confirmed by radiographic examination before and after the crack initiation cycle. Potentials of AE technique for monitoring fatigue crack initiation were discussed.