Background We aimed to determine the relationship of ischaemia-modified albumin (IMA) with diabetic foot ulcers and its predictive value in the Wagner classification. Methods Our cross-sectional study was conducted in 120 diabetic foot patients and 60 healthy individuals with similar body mass index (BMI) and age. Patients with a diabetic foot were classified according to the Wagner classification. Biochemical parameters, C-reactive protein (CRP) and IMA levels were measured in all patients and healthy volunteers. Screening performance characteristics of CRP and IMA were calculated according to Wagner classes and the presence of osteomyelitis. Results The levels of BMI, CRP and IMA in diabetic foot patients were significantly higher than the healthy controls. When we grouped the patients according to the Wagner classification, there were no significant differences between the Wagner groups in terms of BMI. The highest IMA levels were detected in Wagner grade 5. CRP had higher sensitivity and specificity than IMA in the discrimination of other grades, except for grade 4-5 separation. For Wagner grade 4-5 distinction, IMA had 84.6% sensitivity and 94.7% specificity. Conclusion IMA had a higher predictive value in discrimination of the Wagner grade 4-5. In the management of diabetic foot patients, it may be recommended that IMA is evaluated by clinicians.