This study was intended 1) to investigate acoustic realizations of the fortis /s’/ and non-fortis /s/ in Seoul and Yanbian Korean and 2) to explore how a two-way phonemic contrast, /s/ and /s’/, can be compared with a three-way laryngeal contrast of Korean stops in each dialect. Korean fricatives from 10 Seoul and 10 Yanbian Korean speakers were analyzed in terms of fricative duration, center of gravity, F0, H1-H2 and duration of adjacent vowels. This study generated five interesting findings: First, the fortis /s’/ mainly differs from the non-fortis /s/ in frication duration in Seoul Korean. Second, H1-H2 plays a systematic role in differentiating the non-fortis /s/ from the fortis /s’/ in Yanbian Korean. Third, in Yanbian Korean, center of gravity of the non-fortis /s/ is higher than fortis /s’/. Fourth, in Seoul Korean, the fortis /s’/ patterns with tense obstruents, whereas its counterpart /s/ exhibits the phonetic characteristics of lenis and aspirated obstruents. Finally, in Yanbian Korean, the fortis /s’/ shows the properties similar to lenis and tense obstruents, while the non-fortis /s/ demonstrates a comparable pattern as lenis and aspirated obstruents.