This chapter briefly describes the evolution of strike activities as an archetype of union militancy from 1980 to 2016. Strike criteria are not uniform across countries, leading to misleading country-by-country comparisons. Overall, strikes have declined steeply in number since their peak in the 1980s, averaging around 100 per year since 2007. Analyzing the number of strikes by establishment size suggests that unions organized at larger establishments can go on strike to win higher wages, while unions at small or medium-sized establishments cannot achieve the same result under such adverse circumstances. Recent statistics on cases of mediation, adjudication and administrative litigation attest that fewer strikes do not mean a decline in industrial conflicts in the workplace. In terms of wages, data suggests that Korean labor unions’ bargaining power to extract economic rents from employers has declined and their ability to threaten or actualize the use of strikes has become ineffective.