Mycoplasma pneumoniae is a main pathogen causing community-acquired pneumonia in children and young adults. Since the emergence of macrolide-resistant M. pneumoniae in the early 2000s in Japan, it has been increasingly reported worldwide as a growing problem in treatment for children. With increasing macrolide-resistant M. pneumoniae and limited data regarding its characterization and molecular analysis, we investigated the dominant M. pneumoniae strains during the recent outbreak in South Korea, and evaluated if there was an association between a specific type and macrolide resistance. Between October 2014 and December 2016 in South Korea, 249 respiratory specimens obtained from patients with confirmed M. pneumoniae pneumonia were genotyped the P1 adhesin gene, and the mutations associated with resistance (A2063G and A2064G) were tested by sequencing the targeted domain V regions of the 23S ribosomal RNA gene. Results revealed that M. pneumoniae type 1 were predominant, which was strongly associated with macrolide-resistance during the whole study period. This is the first study assessing whether M. pneumoniae subtype is related to macrolide resistance during the outbreak of M. pneumoniae.