Method for detecting that an aircraft is flying in icing conditions, said aircraft being provided with at least one turboengine receiving air coming from an outside medium situated outside the aircraft via an air inlet, said turboengine comprising a gas generator provided with at least one compressor and with a combustion chamber, said turboengine comprising a power assembly provided with at least one power turbine set in rotation by gases escaping from said combustion chamber, in which: - a processing unit determines a real power (Wr) developed by said turboengine as a function of the product of the torque (Tq) developed by said power assembly, measured by a torque measurement system, and of a speed of rotation of the power assembly referred to as the "second speed of rotation " measured by a speed measurement system, - said processing unit determines a theoretical power (Wt) that said turboengine can develop in theory, said theoretical power (Wt) being determined by the processing unit as a function at least of a theoretical model of the turboengine, said theoretical model providing a power as a function at least of a speed of rotation of said gas generator referred to as the "first speed of rotation " measured by a speed measurement means, - the processing unit determines a difference referred to as the "power difference" (ε) between said real power (Wr) and said theoretical power (Wt), - the processing unit generates a warning to indicate the presence of icing conditions when: ∘ said power difference (ε) is greater than a predetermined power threshold for a duration greater than a time threshold (STPS), and ∘ an outside temperature of said outside medium measured by a temperature sensor is comprised between a low temperature threshold (SINF) and a high temperature threshold (SSUP). - a processing unit determines a real power (Wr) developed by said turboengine as a function of the product of the torque (Tq) developed by said power assembly, measured by a torque measurement system, and of a speed of rotation of the power assembly referred to as the "second speed of rotation " measured by a speed measurement system, - said processing unit determines a theoretical power (Wt) that said turboengine can develop in theory, said theoretical power (Wt) being determined by the processing unit as a function at least of a theoretical model of the turboengine, said theoretical model providing a power as a function at least of a speed of rotation of said gas generator referred to as the "first speed of rotation " measured by a speed measurement means, - the processing unit determines a difference referred to as the "power difference" (ε) between said real power (Wr) and said theoretical power (Wt), - the processing unit generates a warning to indicate the presence of icing conditions when: ∘ said power difference (ε) is greater than a predetermined power threshold for a duration greater than a time threshold (STPS), and ∘ an outside temperature of said outside medium measured by a temperature sensor is comprised between a low temperature threshold (SINF) and a high temperature threshold (SSUP). ∘ said power difference (ε) is greater than a predetermined power threshold for a duration greater than a time threshold (STPS), and ∘ an outside temperature of said outside medium measured by a temperature sensor is comprised between a low temperature threshold (SINF) and a high temperature threshold (SSUP).