Serum samples were collected from 153 normoglycaemic, hypoproteinaemic dogs of known case histories, and assayed for fructosamine, glucose, total protein and albumin concentrations. This study was conducted to evaluate the relationship between serum fructosamine and total serum proteins, or more specifically serum albumin. Serum fructosamine was positively correlated with both total serum protein (r = 0.47, p < 0.00001) and serum albumin (r = 0.77, p < 0.00001). Mean serum albumin concentrations were significantly different when the data were grouped as dogs with normal versus subnormal serum fructosamine concentrations. The data indicate the value of the serum fructosamine assay in estimating the duration of hypoalbuminaemia. Concurrent hypoalbuminaemia and normal serum fructosamine indicate hypoalbuminaemia of less than one week. Concurrent hypoalbuminaemia and hypofructosaminaemia indicate persistent hypoalbuminaemia of more than one week, and concurrent normal albumin and hypofructosaminaemia indicate recovery from a condition including hypoalbuminaemia or hypoglycaemia.