Species of Haematoloechus and Rhabdias both are ubiquitous lung parasites of frogs, yet surprisingly little research has been conducted on the interactions between these worms. In a small Nebraska stream, 256 Rhabdias joaquinensis and 225 Haematoloechus complexus were found in the lungs of Lithobates (=Rana) blairi. Thirty-six of the 44 (82%) frogs were co-infected with H. complexus and R. joaquinensis whereas 5 (11%) frogs were infected with only 1 species and 3 (7%) frogs were uninfected. Tests for association between H. complexus and R. joaquinensis found a significant positive relationship between the 2 parasites. Significant positive relationships in intensity of infection were found when both lungs were combined but not when lungs were considered individually. Tests for association between H. complexus and R. joaquinensis found no relationship between the worms in the anterior and posterior portions of the lungs. These data suggest that H. complexus and R. joaquinensis do not competitively exclude each other from the lungs of L. blairi in southeastern Nebraska.