The first local Baptist church in Sweden was founded on the west coast on 21th of September 1848, when five courageous Swedes were baptized by immersion. A Swedish seaman, Fredrik Olaus Nilsson, had been converted in America and returned to Sweden as a preacher. In 1847 he was baptized in Hamburg and became the first Baptist leader in Sweden. As no other religious groups apart from the Lutheran State Church were permitted at this time, Nilsson and others were severely persecuted. Several people were arrested, and Nilsson was banned from the country in 1850. He was very pessimistic about the future of the Baptist movement in Sweden, but by 1860, more than 120 lockal churches had been established.

Despite persecution and legal restrictions, Baptist views spread across the country. In Stockholm, a Lutheran clergyman, Anders Wiberg, wrote a study named "Who is to be baptized and what is baptism?", which was published in 1852. Members of his groups of believers increasingly adopted the ideas of religious freedom and believer's baptism. Some emigrated to America, some went to Hamburg to be baptized, and some were ordained as ministers. Many returned to Sweden when conditions there changed and baptized hundreds of people. By the end of the century, over 500 local churces had been founded.