The effects of intravenous (iv) administration of chlordimeform (CDM) were investigated in 22‐ to 30‐d‐old pentobarbital‐anesthetized Sprague‐Dawley rats. Animals (n = 25) were given sequential iv injections of 5, 10, 30, 60, and 120 mg CDM/kg, or normal saline vehicle followed by a single injection of 60 mg CDM/kg. Heart rate (HR), arterial blood pressure (BP), and electrocardiogram (ECG) were monitored for all animals, while body temperature was maintained at control levels (37°C). CDM produced profound acute effects on all cardiovascular parameters monitored and persistent delayed effects on HR and BP. These effects were similar to but less severe than those observed in a previous study using geriatric animals. Younger animals also appeared to be more resistant to the lethal actions of CDM.