Four mitochondrial (cytrochrome oxidase I) haplotypes of the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), have been identified in North America: western, central, northwestern, and southwestern. A recent study found that females of the northwestern haplotype mated by males of the western or central haplotypes failed to produce viable eggs. Our goal was to determine whether these patterns in reproductive incompatibility are associated with differences among haplotypes in the presence of cytoplasmic incompatibility-inducing bacteria, Wolbachia or Cardinium. Polymerase chain reaction (PCR) revealed that psyllids of the western and central haplotypes were both simultaneously infected with two strains of Wolbachia, but Wolbachia was not detected in psyllids of the northwestern haplotype. PCR using archived DNA from field-collected psyllids confirmed patterns in Wolbachia infection among the western, central, and northwestern haplotypes, and also indicated that Wolbachia was not detectable in psyllids of the southwestern haplotype, which were not available for the mating studies. Cardinium was not detected in psyllids regardless of haplotype. These results provide evidence that differences in Wolbachia infection may be the cause of cytoplasmic incompatibilities among sympatric yet biologically distinct populations of B. cockerelli that have highly divergent mitochondrial haplotypes. This knowledge will improve the interpretation of studies to assess interactions and biological differences among B. cockerelli haplotypes.