Denmark experienced two waves of Mycoplasma pneumoniae infection during autumn and early winter in 2010 and 2011, respectively. Both affected the whole country. The proportion of positive results was almost the same for both, indicating that the two waves were probably of equal size. High macrolide consumption during the epidemics did not seem to affect levels of macrolide resistance in M. pneumoniae, which remain low in Demark (1% to 3%).