The objective of this study was to evaluate cardiovascular and respiratory effects associated with neck flexion, subarachnoid puncture, cerebrospinal fluid drainage and the subarachnoid infusion of ioversol (320mgl/mL) in dogs under isoflurane general anesthesia. The dogs received infusion of: autologous cerebrospinal fluid at 38 degrees C (GC - control group); ioversol 0.3mL/ Kg at 25 degrees C (GI25) and heated to 38 degrees C (GI38). Heart rate, systolic and diastolic arterial pressure, respiratory rate, oxyhemoglobin saturation and electrocardiography readings were recorded. The results showed that cervical myelography with ioversol 320mgl/mL at 0.3mL/Kg (25 C-degrees and 38C degrees) did not significantly alter recorded parameters, except for an elevation in arterial pressure.