Spontaneous bacterial peritonitis (SBP) occurs most frequently in patients with cirrhosis and preexistent ascites; SBP has not been previously recognized in association with acute liver disease. We report two patients with acute hepatitis B infection who developed SBP. Patient 1 had Streptococcus pneumoniae peritonitis and bacteremia, but did not have ascites until after the peritoneal infection was evident. Subsequent liver biopsy and follow-up studies confirmed the clinical diagnosis of acute hepatitis. Patient 2 had submassive hepatic necrosis due to hepatitis B and developed ascites before Streptococcus fecalis SBP. Although the association of SBP with acute hepatic injury is rare, these two patients illustrate that the syndrome of SBP does occur with acute liver disease.