As part of the Bottlenose Dolphin Health and Risk Assessment study, blood, gastric, fecal, and blowhole samples were collected from 114 Atlantic bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida (IRL), and from 73 dolphins from the estuarine waters around Charleston, South Carolina (CHS), to assess the presence and degree of cytologic evidence of gastric inflammation from 2003 to 2007. The prevalence of moderate and severe gastric inflammation was 9.6% in the IRL and 11.0% at CHS. A case-control study of 19 dolphins with cytologic evidence of gastric inflammation and 82 with normal cytology from the combined populations was conducted. Blood parameters evaluated included hematology, serum chemistry, serum protein electrophoresis, and stress hormones. Few differences of clinical or statistical significance were found between affected and unaffected dolphins. Serum norepinephrine and cortisol were significantly higher in cases compared to the controls, and aldosterone was marginally higher (P = 0.06) based on eight cases. None of the hematologic, serum chemistry, or serum electrophoresis results were significantly different. Gastric fluid pH was not significantly different between cases and controls. There were no clinically significant aerobic-anaerobic or fungal culture results from gastric contents; bacteria cultured from both groups were considered to represent normal flora. The prevalence of inflammation did not differ by gender. Historically, cytologic evidence of gastric inflammation has constituted a marker of systemic illness in dolphins; however, there was little evidence to indicate systemic illness among affected animals. The data obtained from this study provide a basis for further investigation and evaluation of gastric cytology in wild and managed bottlenose dolphins.