Recently, the term of spirituality is drawing people’s special attention, in particular, in Christianity. However, for the diverse or multi-meanings of spirituality, it is neither easy to define it clearly, nor to use it suitably. In this paper, I try to approach this theme focusing on the history of Christian mysticism, in particular, Protestant one. In general, the mainstreams in Church history have tended to know God in academic ways. But, one can find that there have been other ways to approach God, which has been known as mysticism. While there is a strong tendency to identify mysticism with superstition in Korea, mysticism has a long history in Christianity, seeking a spiritual union with God. During the Middle Age, monasteries were the center of mysticism. However, in the case of Protestantism, where monasticism could not find its place, such a tradition persistently has appeared in a variety of forms and ways. During the Reformation, the Reformers focused their attentions on the doctrine of justification by faith, while Anabaptists had more concern about the mystical and moral aspects of Christian life. In the 17th century, however, Pietism and Puritanism began to appear paying more attention to the changed life of Christians. As a result, regeneration and sanctification became popularized along with, or even instead of justification. During the 18th century, spiritual experience became a central concern for many evangelicals in the American colonies as well as the Great Britain. The pivotal figures during the First Great Awakening preached a series of sermons on regeneration or conversion. They emphasized the significance of spiritual experience by revivals which led believers to the higher state of piety, that is, sanctification or holiness. Such a trend persisted during the nineteenth century. A variety of holiness movements sought to have the experience of entire sanctification by the Baptism of the Holy Spirit. In the case of Charles G. Finney, however, he attempted to synthesize both personal holiness and social reform in his controversial revivals. The twentieth century opened its door with the appearance of Pentecostalism. This radical version of holiness movement shaped its theological and spiritual identity by placing its primary emphasis upon the doctrine of speaking in tongue as the physical sign of the Baptism of the Holy Spirit. By this new movement, the Holy Spirit became more popularized, and the Charismatic experiences became one of the most serious concerns of modern Christians regardless of their denominational differences. Currently, the so-called “Emerging Church” is drawing a more fresh and attractive attention from many Christians, which tries to apply the ancient types of spirituality to the postmodern atmosphere. Likewise, the Protestant spirituality has been trying to find or construct its path in a variety of ways. Such a sacred struggling is still going on.