In a case-finding campaign against diabetes, duplicate dried samples of urine were obtained on test-papers from 19,403 persons. In 665 cases there was a positive reaction to one or both of 2 tests for glucose. The Benedict test was positive in 49% of the 665 cases; the glucose-oxidase test was positive in 90%. Both were positive in 39%. In 114 cases it was possible to perform both a postprandial blood sugar (PBS) determination and a glucose-tolerance test (GTT). Among these there were 21 who would be classified as diabetic by the PBS but normal by the GTT, and 19 normal by the PBS but diabetic or probably diabetic by the GTT.