Computed tomography (CT) diagnosis of pneumatosis involving the gastrointestinal tract can represent a broad range of clinical entities from a benign process to ischemic bowel. The purpose of this study is to define the significance and outcome of pneumatosis intestinalis (PI). All CT scans from 5/93 to 12/01 with the finding of PI were reviewed. Eighty-six CT scans had the finding of PI, with the colon being the most frequent location (51%), followed by small bowel (36%) and gastric (9%). Forty per cent of patients underwent surgery, with an overall mortality rate of 42 per cent and a surgical mortality rate of 47 per cent. Univariate analysis demonstrated significant correlation between serum lactic acid (LA) >2.0 mmol/L [odds ratio (OR) = 23.4; 95% confidence interval (CL), 7.21-75.92] and serum creatinine >1.5 mg/dL (OR = 3.05; 95% CL, 1.25-7.42) with mortality. Age was suggestive but not a significant risk factor for mortality (P = 0.09). Multivariate analysis found serum LA >2.0 (OR = 30.37; 95% CL, 7.31-126.2) to be the only significant predictor of mortality. CT diagnosis of PI is associated with significant in-hospital mortality, especially in the elderly. Serum LA level >2.0 mmol/L at time of diagnosis is associated with a greater than 80 per cent mortality. Surgical consultation is necessary to determine which patients need urgent surgical intervention.