The stink bug Nezara viridula has one major bacterium associated with the last section of its midgut (V4), where the gastric caeca are located. Little is known about its biology or importance to N. viridula. It has been hypothesized that pentatomid females smear this symbiont on the surface of eggs during oviposition. In that case, first instar nymphs would hatch without this bacterium (aposymbiotic nymphs), and acquire it orally from the surface of eggs. We tested different concentrations of alcohol and bleach to surface sterilize egg masses of N. viridula, and studied the vertical transmission of this symbiont. We kept half of the egg mass as control and the other half was surface sterilized. PCR symbiont-specific primers were used to detect the bacterium in the V4 section of nymphs and adults. In the first generation, 88% of the control (symbiotic) and 10% of the treated insects had the symbiont, respectively. In the second generation, treated replicates were 100% aposymbiotic and 17% of the control individuals were free of this symbiont. Vertical transmission of this bacterium occurs orally. We observed no fitness decrease in aposymbiotic insects (kept for four generations).