An apparatus for washing and dewatering pulp comprising a first and a second rotatable press roll (102, 104) having a permeable outer surface (106, 108), and a casing comprising a vat (114, 116, 118) in which the press rolls (102, 104) are installed, the press rolls (102, 104) defining a press nip (112) between them, in which press nip (112) the pulp is pressed. The vat (114, 116, 118) com- prises a first side vat segment (114) which partly encloses the outer surface (106) of the first press roll (102) and a second side vat segment (116) which partly en- closes the outer surface (108) of the second press roll (104). The casing comprises a first side casing member (115) provided with the first side vat segment (114) and a second side casing member (117) provided with the second side vat segment (116), at least the first side casing member (115) being pivotable about a rotationaxis(121). The apparatus comprises a first pulp distribution device (126) for distributing pulp on the first press roll (102) and a second pulp distribution device (128) for distributing pulp on the second press roll (104), where at least the first pulp distribution device (126) is mounted on the first side casing member (115), whereby the first pulp distribution device (126) is moved away from the first press roll (102) together with the first side casing member (115) when this is moved from its closed position to its opened position.