The aim of our study was to investigate the behavioral and electroencephalographic manifestations of thioacetamide-induced encephalopathy in rats. Male Wistar rats were divided among (i) control, saline-treated, and (ii) thioacetamide-treated groups (TAA₃₀₀ (300 mg/kg body mass); TAA₆₀₀ (600 mg/kg); and TAA₉₀₀ (900 mg/kg)). The daily dose of thioacetamide (300 mg/kg) was administered intraperitoneally once (TAA₃₀₀), twice (TAA₆₀₀), or 3 times (TAA₉₀₀), on subsequent days. Behavioral manifestations were determined at 0, 2, 4, 6, and 24 h, while electroencephalographic changes were recorded 22–24 h after the last dose. General motor activity and exploratory behavior, as well as head shake, auditory startle reflex, placement, and equlibrium tests were diminished in the TAA₆₀₀ and TAA₉₀₀ groups compared with the control, and were absent in the TAA₉₀₀ group 24 h after treatment. Corneal, withdrawal, grasping, and righting reflexes were significantly diminished in the TAA₉₀₀ group compared with the control. Mean electroencephalographic power spectra density was significantly higher in TAA₃₀₀ and TAA₆₀₀ and lower in the TAA₉₀₀ group by comparison with the control. Only a score of 3 (mean dominant frequency ≤ 7.3 Hz and δ relative power ≥ 45%) was observed in the TAA₉₀₀ group. Thioacetamide induces encephalopathy in rats in a dose-dependent manner. A dose of 900 mg/kg TAA may be used as a suitable model of all stages of hepatic encephalopathy.