A method for transferring a registration of three dimensional image data of a surgical object from a first to a second surgical navigation system , wherein a first tracker (34; 54) that is detectable by a first detector of the first surgical navigation system is arranged in a fixed spatial relationship with the surgical object and a second tracker (36; 56) that is detectable by a second detector of the second surgical navigation system is arranged in a fixed spatial relationship with the surgical object , the method comprising registering the three dimensional image data of the surgical object in a first coordinate system of the first surgical navigation system ; determining a first position and orientation of the first tracker (34; 54) in the first coordinate system and a second position and orientation of the second tracker (36; 56) in a second coordinate system of the second surgical navigation system ; determining a third position and orientation of the second coordinate system in the first coordinate system ; and registering the three dimensional image data of the surgical object in the second coordinate system on the basis of the determined first, second and third positions and orientations, wherein registering the three dimensional image data of the surgical object in the second coordinate system comprises determining a spatial relationship of the first tracker relative to the second tracker on the basis of the determined first, second and third positions and orientations, and wherein determining the third position and orientation comprises at least one of determining a position and orientation of a third tracker that is detectable by the first detector of the first surgical navigation system , wherein the third tracker is arranged in a known position and orientation in the second coordinate system ; and determining a position and orientation of a fourth tracker that is detectable by the second detector of the second surgical navigation system , wherein the fourth tracker is arranged in a known position and orientation in the first coordinate system . registering the three dimensional image data of the surgical object in a first coordinate system of the first surgical navigation system ; determining a first position and orientation of the first tracker (34; 54) in the first coordinate system and a second position and orientation of the second tracker (36; 56) in a second coordinate system of the second surgical navigation system ; determining a third position and orientation of the second coordinate system in the first coordinate system ; and registering the three dimensional image data of the surgical object in the second coordinate system on the basis of the determined first, second and third positions and orientations, wherein registering the three dimensional image data of the surgical object in the second coordinate system comprises determining a spatial relationship of the first tracker relative to the second tracker on the basis of the determined first, second and third positions and orientations, and wherein determining the third position and orientation comprises at least one of determining a position and orientation of a third tracker that is detectable by the first detector of the first surgical navigation system , wherein the third tracker is arranged in a known position and orientation in the second coordinate system ; and determining a position and orientation of a fourth tracker that is detectable by the second detector of the second surgical navigation system , wherein the fourth tracker is arranged in a known position and orientation in the first coordinate system . <EOS>