The brown marmorated stink bug, Halyomorpha halys, is an invasive, highly polyphagous pest of many agricultural crops, including fruit crops. To identify a potential biocontrol agent, the cultivable microbiota within the gut of 32 H. halys specimens collected during three sampling occasions from three different habitats in the Zurich region were examined. No culturable microbiota could be detected in 47% of the samples. Strains from the genera Pseudomonas and Enterococcus as well as the species Yokenella regensburgei and Acinetobacter johnsonii were the most abundant isolates. Due to the high beta diversity between the microbiota of H. halys specimens, no characteristic core microbiota could be determined. With the exception of one, all bacterial species that colonized the intestines of H. halys with a CFU higher than 104 are assigned to the biosafety level 2 and are therefore not suitable as biological control candidates.