The effects of different preanesthetic medications (acepromazine plus either meperidine or butorphanol) given before the induction of anesthesia with midazolam and ketamine on intraocular pressure, heart rate, and arterial blood pressure were investigated in 20 dogs. Following administration of preanesthetics and induction of anesthesia, dogs were intubated and anesthesia was maintained with halothane for 10 minutes. Intraocular pressure was significantly higher (P <.05) at several evaluations for dogs premedicated with acepromazine/meperidine than for those premedicated with acepromazine/butorphanol. Mean heart rate and diastolic arterial blood pressure were significantly (P <.05) higher 5 minutes after administration of acepromazine/meperidine than after acepromazine/butorphanol. Results of this study suggest that acepromazine/butorphanol is a satisfactory preanesthetic combination to use before induction of anesthesia with midazolam and ketamine for ophthalmic surgery in dogs.