Coagulation assays, including platelet counts, antithrombin III, fibrinogen, fibrinogen degradation product levels, prothrombin (PT), activated partial thromboplastin (APTT) and activated clotting times (ACT), were performed on 20 healthy juvenile northern elephant seals (Mirounga angustirostris) stranded along the central California coastline from 15 March to 15 April 1994, to establish baseline parameters for this species. Elephant seals appear to have relatively short ACT, PT, and APTT times, while fibrinogen, platelet and antithrombin III levels are similar to domestic species. Based on these mean values in healthy animals, disseminated intravascular coagulation (DIC) was diagnosed in an elephant seal with low plasma fibrinogen and extended ACT, PT and APTT times; this animal had hemorrhages, mixed bacterial suppurative interstitial pneumonia with verminous arteritis, epicarditis, hepatitis and enterocolitis.