In patients suffering from clinically manifest atherosclerosis autologous LDL-labelling has been done using 123I. This technique allows localization of areas with an increased LDL entry as well as a monitoring of kinetics. Normally, no tracer uptake can be seen in the vascular system. Positive camera images, however, can be obtained in pathological areas as early as 60 min after LDL-reinjection. Experimental data and morphological control reveal a very good correlation to the gamma-camera findings. The technique seems to be very promising for diagnosis in patients suffering from atherosclerosis and hyperlipoproteinemia.