OBJECTIVE To evaluate whether measurement of albumin creatinine ratio (ACR) on a spot urine specimen can replace a timed overnight collection of urine albumin excretion rate (UAER) in patients with diabetes in primary care. METHODS Patients with diabetes attending Rønvik Health Centre were asked to bring a timed overnight collection of urine for measurement of UAER. They were also asked to void a urine specimen for measurement of albumin creatinine ratio. METHODS Primary health care. METHODS One-hundred-and-six persons with diabetes (47 women, 59 men) aged 13 to 78 years. RESULTS The sensitivity and specificity of ACR with cut-off values of 2.5 mg/mmol for men and 3.5 mg/mmol for women compared to UAER with cut-off value of 20 mg/24 h was 90%. CONCLUSIONS Spot urine ACR analysed on a DCA 2000 can replace a timed (overnight) collection of urine and measurement of UAER when diabetic patients are reviewed in general practice. This simplifies procedures for the patient as a timed urine collection is no longer necessary. Another advantage is that the results are available after 7 min.