Abstract: The present invention relates to an electro-pneumatic positioner for use with a pneumatically controlled two-chamber actuator comprising a first valve unit (10) comprising a first air supply valve (14) and a first air outlet valve (37) connected to a conduit (30, 38, 50), which in turn is connectable to a chamber of the actuator, a second valve unit (12) comprising a second air supply valve (14′) and a second air outlet valve (37′) connected to a conduit (30′, 38′, 50′), which in turn is connected to a second chamber of the actuator; a first control device (60, 74) acting on the first air supply valve, which first control device comprises a first control valve (60); a second control device (60′, 76) acting on the said second air supply valve, which second control device comprises a second control valve (60′).