A cooling system for immersed computing devices, comprising: - a cooling bath tank that contains a cooling fluid that flows through the inside thereof from at least one outlet to at least one inlet, in which said cooling bath tank is designed and arranged to enable at least a first portion of at least one computing device to be cooled to be inserted therein, said computing device being at least partially immersed in the cooling fluid contained therein, and - at least one cooling unit designed to collect and cool the cooling fluid flowing out of said at least one inlet and to return the cooling fluid, once cooled, through said at least one outlet into said cooling bath tank, designed to be inserted into said cooling bath tank, to be at least partially immersed in the cooling fluid contained therein, and to be removed therefrom, and including a casing with projections designed and arranged to be supported at least by supports projecting inwards from internal walls of the cooling bath tank when the cooling unit is inserted into the cooling bath tank, the casing having a first compartment and a second compartment that are fluidly isolated from one another, said first compartment fluidly connected with the at least one outlet and having an inlet to enable the cooling fluid coming out of the at least one outlet in the cooling bath tank to enter said first compartment in which said first compartment houses a fluid pump that is immersed in the cooling fluid that has entered through said inlet of the first compartment and that is designed and arranged to pump said cooling fluid to the inlet of the first circuit of the heat exchanger that is housed in said second compartment and designed to cool the fluid flowing through said first circuit, in which said first compartment has a first sub-compartment (7a1) and a second sub-compartment (7a2), said second sub-compartment (7a2) fluidly connected with the at least one outlet, and in which said first compartment (7a1) has said inlet to enable the cooling fluid to enter said first sub-compartment, and in which said first sub-compartment (7a1) at least partially houses the fluid pump, comprising a suction inlet therein that is immersed in the cooling fluid that has entered through said inlet of the first compartment, and that is designed and arranged to pump said cooling fluid to the inlet of the first circuit of the heat exchanger that is housed in said second compartment and designed to cool the fluid flowing through said first circuit by means of a refrigerant fluid that is flowing through a second circuit of the heat exchanger, enabling the cooled down cooling fluid flowing through said first circuit of said heat exchanger to flow to the second sub-compartment (7a2) through cooling-fluid outlet arranged therein. - a cooling bath tank that contains a cooling fluid that flows through the inside thereof from at least one outlet to at least one inlet, in which said cooling bath tank is designed and arranged to enable at least a first portion of at least one computing device to be cooled to be inserted therein, said computing device being at least partially immersed in the cooling fluid contained therein, and - at least one cooling unit designed to collect and cool the cooling fluid flowing out of said at least one inlet and to return the cooling fluid, once cooled, through said at least one outlet into said cooling bath tank, designed to be inserted into said cooling bath tank, to be at least partially immersed in the cooling fluid contained therein, and to be removed therefrom, and including a casing with projections designed and arranged to be supported at least by supports projecting inwards from internal walls of the cooling bath tank when the cooling unit is inserted into the cooling bath tank, the casing having a first compartment and a second compartment that are fluidly isolated from one another, said first compartment fluidly connected with the at least one outlet and having an inlet to enable the cooling fluid coming out of the at least one outlet in the cooling bath tank to enter said first compartment in which said first compartment houses a fluid pump that is immersed in the cooling fluid that has entered through said inlet of the first compartment and that is designed and arranged to pump said cooling fluid to the inlet of the first circuit of the heat exchanger that is housed in said second compartment and designed to cool the fluid flowing through said first circuit, in which said first compartment has a first sub-compartment (7a1) and a second sub-compartment (7a2), said second sub-compartment (7a2) fluidly connected with the at least one outlet, and in which said first compartment (7a1) has said inlet to enable the cooling fluid to enter said first sub-compartment, and in which said first sub-compartment (7a1) at least partially houses the fluid pump, comprising a suction inlet therein that is immersed in the cooling fluid that has entered through said inlet of the first compartment, and that is designed and arranged to pump said cooling fluid to the inlet of the first circuit of the heat exchanger that is housed in said second compartment and designed to cool the fluid flowing through said first circuit by means of a refrigerant fluid that is flowing through a second circuit of the heat exchanger, enabling the cooled down cooling fluid flowing through said first circuit of said heat exchanger to flow to the second sub-compartment (7a2) through cooling-fluid outlet arranged therein.