Generalized subcutaneous abscessation followed by acute systemic infection occurred in a young male harbor seal (Phoca vitulina richardii). Clinically, infection was manifested by malaise, progressive weight loss, labored respiration, intermittant vomitation, and mucohemorrhagic diarrhea. A coagulase-positive Staphylococcus aureus was isolated from the subcutaneous abscesses, and specimens of lung, liver, small intestine, and kidney. Microscopically, cysts and trophozoites of Toxoplasma gondii were found in, or adjacent to, foci of necrosis present throughout the liver parenchyma.