Acepromazine and propofol are two drugs commonly used in veterinary medicine for sedation or anesthesia. Limited studies using acepromazine in dogs have suggested that this drug may prolong platelet aggregation and therefore have a negative effect on primary hemostasis. Propofol has been extensively studied in human medicine, in which it has been variably associated with decreased or unaltered platelet aggregation. There has been little investigation of potential adverse effects using these drugs in dogs. The purpose of this study was to evaluate the effect of these two drugs, alone and in combination, on primary and secondary hemostasis in dogs. Eight healthy purpose-bred Beagles received saline control, acepromazine (0.05 mg/kg IV), propofol (4 mg/kg IV) or acepromazine and propofol in combination, in a randomized, blinded study design. All dogs received each treatment once, with a two-week washout period to minimize possible carryover effect. Blood was collected prior to and after the administration of the drug. Platelet aggregation was evaluated by optical aggregometry and whole blood aggregometry using a platelet function analyzer (PFA-100®). Other parameters evaluated included prothrombin time, partial thromboplastin time, fibrinogen level, platelet count, total solids, hematocrit and total white blood cell count. No effect on platelet aggregation was noted after administration of these drugs, individually or in combination. Acepromazine, alone and in combination with propofol, was associated with a significant decrease in the hematocrit, red blood cell count, platelet count and total solids (p<0.05). Acepromazine, alone and in combination with propofol, was also associated with a decrease in the prothrombin time. With the exception of hematocrit, all post-treatment parameters remained within the normal reference intervals. In summary, neither acepromazine nor propofol administration caused a defect of primary or secondary hemostasis in normal dogs. Though statistically significant, the magnitude of the changes in platelet count and prothrombin level is unlikely to be clinically relevant in healthy dogs.