This study was initiated to understand the role of minor cyclic loading, a typical scenario of pressure fluctuations during the operation of high-pressure gas transmission pipelines, in overall crack growth of X60 pipeline steel in near-neutral pH solution.A loading waveform consisting of small constant amplitude cycles with a high R ratio (minimum stress/maximum stress) of 0.9 and periodic single underloading cycle with R ratio of 0.5 was designed and applied to compact tension specimens to induce crack growth in air and in nearneutral pH environments, respectively.To further confirm the role of minor cyclic loading, crack growth under a loading waveform consisting of static hold replacing the minor loading cycles and the periodic underload cycles was also determined.It has been found that the minor cyclic loading could enhance the crack growth in the presence of underloads by a factor of 4.2 and 2.1, respectively, in air and in near neutral pH environment.Static holding could actually reduce the crack growth rate of underloading cycles by a factor of 0.35 in near-neutral pH solution.The possible mechanisms on the role of minor cyclic loading in overall crack growth were also discussed in the paper.