The effect of exposure to diabetes on the kidney appears to be modulated by genetic factors determining a variable degree of susceptibility to diabetic nephropathy. Multiple loci are probably involved. Some of them might be found among the genes coding for components of the renin angiotensin system (renin, angiotensinogen, angiotensin I-converting enzyme, angiotensin receptors), some may regulate the way in which cells manage hyperglycemia (e.g. aldose reductase). Various genes have been examined to date, mainly by means of association studies. Positive results have been found for some of them (e.g. ACE, AGTR1, aldose reductase), but have not been confirmed in other populations. Thus, no genetic marker of increased susceptibility to diabetic nephropathy having clinical utility is currently available. New insights are expected from the systematic scanning of the genome for linkage with diabetic nephrophathy.