An improved muffle for cooking ovens particularly for food and the like, comprising two substantially C-shaped parts (11, 12), which face each other with their respective concavities so as to form a cooking compartment (13), which is closed at the rear by a back (14); the two parts (11, 12) are connected to each other and to the back (14) by way of corresponding flaps (11a, 11b, 11c, 12a, 12b, 12c, 14a, 14b, 14c) that are coupled by way of connecting means. The connecting means are constituted by threaded elements (15); gasket elements suitable to contain the escape of hot air from the muffle (10) are interposed between the lateral connecting flaps (11a, 11b, 12a, 12b) of the two parts (11, 12) and between at least part of the rear flaps (11c, 12c) of the two parts (11, 12) and the flaps (14c) of the back (14).