Abstract The safety of Algal Oil from Schizochytrium sp. was evaluated by testing for gene mutations, clastogenicity and aneugenicity, and in a subchronic 90-day Sprague–Dawley rat dietary study. The results of all genotoxicity tests were negative. The 90-day study involved dietary exposure to 0.5, 1.5, and 5wt.% of Algal Oil and two control diets: a standard low-fat basal diet and a basal diet supplemented with 5wt.% menhaden oil (the fish oil control). There were no treatment-related effects of Algal Oil on clinical observations, body weight, food consumption, behavior, hematology, clinical chemistry, coagulation, or urinalysis parameters. Increased mean liver weights and alveolar histiocytosis were observed in both the fish oil control and the high-dose Algal Oil-treated animals and were not considered to be adverse. Algal Oil was bioavailable as demonstrated by the dose-related increase of DHA and EPA levels in tissues and plasma. The no observable adverse effect level (NOAEL) for Algal Oil under the conditions of this study was 5wt.% in the diet, equivalent to an overall average Algal Oil intake of 3250mg/kg bw/day for male and female rats. Based on the body surface area, the human equivalent dose is about 30g Algal Oil/day for a 60kg adult.