This paper reports a case of S. constellatus chorioamnionitis in a pregnant Crohn's disease patient who was taking azathioprine. Chorioamnionitis is a major cause of perinatal morbidity. Azathioprine, an immunosuppressive antimetabolite, is widely used to treat inflammatory bowel disease. Streptococcus constellatus is a Gram-positive bacterium that has not previously been associated with chorioamnionitis. A high index of suspicion for chorioamnionitis and unusual pathogens should be maintained in the management of obstetric patients on immunosuppressive agents.