As design life of nuclear power plant is expanded over 60 years, the environmentally assisted fatigue (EAF) due to exposure to the reactor coolant environment has been considered as one of the important damage mechanisms of the safety class 1 components. Many EAF test results including Argonne National Laboratory’s to evaluate the effect of light water reactor (LWR) coolant environments on fatigue life of materials have been conducted. However, there is a discrepancy between laboratory test data and plant operating experience regarding the effects of environment on fatigue. Therefore, it is necessary to clarify the effects of light water environments on fatigue life while considering more plant-relevant transient conditions such as strain holding. For this reason, this study focused on the effect of strain holding on fatigue life of type 316 stainless steel during the low cycle fatigue (LCF) test in simulated LWR environments. To simulate the heat-up and cooldown transient, sub-peak strain holding during the down-hill of strain amplitude was chosen. For 0.4% strain amplitude, LCF tests with 60 and 300 seconds strain holding were conducted. Our test results showed that the fatigue life of strain holding condition was slightly longer than that of the reference test conditions.