Antrodia cinnamomea (Ac) is a medicinal mushroom widely used for the treatment of abdominal pain, hypertension and hepatocellular carcinoma, but subchronic toxicity of this material has not yet been investigated. This present study was conducted to assess the 90-day oral toxicity of A. cinnamomea from submerged culture in male and female Sprague-Dawley (SD) rats. Eighty rats were divided into four groups, each consisting of ten male and ten female rats. Test articles were administered by oral gavage to rats at 3000, 2200 and 1500 mg/kg BW/day for 90 consecutive days and reverse osmosis water was used as control. All animals survived to the end of the study. During the experiment period, no abnormal changes were observed in clinical signs, body weight and ophthalmological examinations. No significant differences were found in urinalysis, hematology and serum biochemistry parameters between the treatment and control groups. Necropsy and histopathological examination indicated no treatment-related changes. According to the above results, the no-observed-adverse-effect level (NOAEL) of Antrodia cinnamomea is identified to be greater than 3000 mg/kg BW/day in Sprague-Dawley rats.