A downhole gas-liquid separator for multiphase fluid producing wells includes a tubular member with a spiral baffle disposed therein and a duct including an inlet disposed adjacent the discharge end of the spiral baffle. Fluid flow into the separator undergoes substantial gas and liquid separation by centrifugal forces imposed on the liquid as it progresses through the spiral flowpath. Gas is drawn off at the discharge end of the spiral baffle and discharged into the wellbore annulus while liquid and a small amount of gas pass on through the separator and the production tubing to the surface. The spiral baffle may be disposed in the wellbore between the distal end of the production tubing string and the point of entry of gas and liquid into the wellbore. The separator may include a retrievable tubular body inserted in a ported nipple interposed in the tubing string.