The effects on respiration upon stimulation of different areas of cerebral cortex were studied in 38 urethance anesthetized rabbits after both vagotomy and section of the maxillary division of trigeminal nerves. The results showed that: (1) Light continuous stimulations of the limb motor area (L) enforced inspiration by increasing respiratory frequency (RF) and tidal volume (TV). Stimulation of the facial motor area (F) increased RF notably, but depth of expiration and inspiration were notably decreased. Upon stimulation of the masticatory motor area (M), expiration or inspiration was accentuated, RF and TV were obviously increased. Upon stimulation of the posterior orbital area RF and TV were decreased markably. No obvious effects on respiration were observed on stimulation of the other areas of the cortex. (2) With shortened total period of stimulation, a stimulating L, F or M area would cause a longer period of apnoea after expiration and resumption of inspiration insured an increased TV.