Mould for realizing a temporary prosthesis of hip or shoulder, which temporary prosthesis of hip or shoulder comprises a shaft and a head fixed to the shaft, wherein the mould comprises: a first mould portion comprising a first half-shell; a second mould portion comprising a second half-shell; the first mould portion and the second mould portion being able to be coupled with respect to each other so that, when coupled, the first half-shell and the second half-shell are counter-faced and define a chamber which conforms a shaft portion, a head portion and an opening for injection in the same chamber of a suitable fluid material for a temporary prosthesis of hip or shoulder; fixing means for fixing the first mould portion and the second mould portion removably with respect to each other when the first mould portion and the second mould portion are coupled together; and a first insert comprising a cap portion, which cap portion is realized as a unique body, is dimensioned to be inserted in the head portion of the chamber, is in contact to the first half-shell and the second half-shell, and is provided to give the shape to the head of the desired temporary prosthesis of hip or shoulder; the first mould portion, the second mould portion and the first insert are mutually conformed to obtain a temporary prosthesis of hip or shoulder, when the first mould portion and the second mould portion are coupled together, the first insert is inserted in the head portion of the chamber and the viscous material is injected in the opening; characterized by comprising supporting means for supporting the first mould portion and the second mould portion when the first mould portion and the second mould portion are coupled together so that the head portion is under the shaft portion, so that by adjusting the quantity of fluid material injected in the opening it is possible to set the length of the shaft of the desired temporary prosthesis of hip or shoulder. a first mould portion comprising a first half-shell; a second mould portion comprising a second half-shell; the first mould portion and the second mould portion being able to be coupled with respect to each other so that, when coupled, the first half-shell and the second half-shell are counter-faced and define a chamber which conforms a shaft portion, a head portion and an opening for injection in the same chamber of a suitable fluid material for a temporary prosthesis of hip or shoulder; fixing means for fixing the first mould portion and the second mould portion removably with respect to each other when the first mould portion and the second mould portion are coupled together; and a first insert comprising a cap portion, which cap portion is realized as a unique body, is dimensioned to be inserted in the head portion of the chamber, is in contact to the first half-shell and the second half-shell, and is provided to give the shape to the head of the desired temporary prosthesis of hip or shoulder; the first mould portion, the second mould portion and the first insert are mutually conformed to obtain a temporary prosthesis of hip or shoulder, when the first mould portion and the second mould portion are coupled together, the first insert is inserted in the head portion of the chamber and the viscous material is injected in the opening; characterized by comprising supporting means for supporting the first mould portion and the second mould portion when the first mould portion and the second mould portion are coupled together so that the head portion is under the shaft portion, so that by adjusting the quantity of fluid material injected in the opening it is possible to set the length of the shaft of the desired temporary prosthesis of hip or shoulder.