We analyzed 927 wild boars (Sus scrofa) in southwestern Spain during the hunting seasons of 2004/2005 to 2008/2009. Respiratory tracts were examined for lung nematodes (Metastrongylus spp.). The prevalence of Metastrongylus spp. was 41.1%. The most frequently isolated species were Metastrongylus apri (71.4%), Metastrongylus pudendotectus (28.0%), and Metastrongylus salmi (0.6%). Prevalence and infection intensity were greater in young animals (<1 yr old) than in older animals. There were no significant differences in prevalence between sexes. Prevalence and intensity of infection were higher in areas of high altitude and high rainfall.