AIMS: We aimed to characterize the determinants and characteristics of renal disease in very old diabetic patients in geriatric care. METHODS: Consecutive diabetic patients (96 women, 38 men) admitted to a geriatric service were studied. Glomerular filtration rate (GFR), albuminuria, vascular and general comorbidities, glycaemic control, malnutrition (using the Mini-Nutritional Assessment [MNA], serum albumin and cholesterol levels), haemoglobin and inflammation (CRP levels) were assessed. RESULTS: (a) 51.2 and 12.4% patients had moderate or severe renal insufficiency. The prevalence of normo-, micro- and macroalbuminuria was 45.0, 38.9 and 16.0% in the whole population, and was similar in patients with or without moderate renal insufficiency. Renal insufficiency was associated with previous stroke (P=0.024), heart failure (P=0.024), and atrial fibrillation (P=0.008), and possibly myocardial infarction (P=0.059, Mann-Whitney test). (b) Albuminaemia was associated with albuminuria, MNA scores, haemoglobin, total and HDL-cholesterol and CRP. However, in multiple linear regression analysis CRP was the only robust determinant of albuminaemia (P<0.0001). (c) Renal insufficiency was not associated with the MNA, serum albumin, haemoglobin and cholesterol levels. CONCLUSION: Renal insufficiency often occurs without albuminuria, suggesting aetiologies distinct from classical diabetic nephropathy, and is strongly associated with vascular comorbidities. Hypoalbuminaemia is more strongly associated with inflammation than with albuminuria and malnutrition. Malnutrition, hypoalbuminaemia, low cholesterol levels and anaemia are not associated with renal insufficiency, likely due to the very high prevalence of these abnormalities in the whole population. These features must be taken into account when organizing the global care of elderly diabetic patients.