Abstract: A chimney ventilating cap for the evacuation of combustion gas from chimneys. The cap comprises a spherical hollow dome body defined by a forward and a rear partly semi-spherical body portion. The front and rear body portions are secured together in a spaced-apart manner to define an opening between their circumferential edges. A shield is associated with the opening. A wind governor is secured to the rear body portion. The hollow dome body has a vertical pivot connection secured to an open-ended attachment base whereby the dome body is pivotal on the vertical pivot to rotate on the base by change in wind direction.