A study was conducted to evaluate the presence of the infectious hypodermal and hematopoietic necrosis virus (IHHNV) in wild parent stocks of blue shrimp, Penaeus stylirostris, in Guaymas Bay, Sonora, Mexico. The procedure used to detect the virus was the ShrimpProbe Test Kit Dot Blot, DiagXotic, Inc. Results showed that the virus was present in 49% of the 100 shrimp studied. Males were more infected (54%) than females (44%). Infection in both sexes was more frequent in size classes 36–40 and 31–35 mm. For males, the highest percentages of infections were found in size classes 36–40, 31–35 and 46–50 mm; for females, in size classes 36–40, 31–35 and 41–45 mm (only size classes from 31–35 to 51–55 mm were considered).