To examine the correlations of miR‐24 expression in peripheral plasma with the onset of diabetic foot ulcer (DFU) and diabetic foot osteomyelitis (DFO) in type 2 diabetes mellitus (T2DM) patients and explore the clinical value of miR‐24 as a potential biomarker for the diagnosis and treatment outcomes of DFU and DFO, a total of 60 newly diagnosed T2DM patients without DFU (T2DM group), 112 T2DM patients with DFU (DFU group), and 60 healthy controls (NC group) were included. DFU group were further divided into DFO group (n = 64) and non‐DFO group (n = 48). MiR‐24 levels were determined by quantitative real‐time PCR, while clinical features and risk factors of DFU and DFO were explored. The expression level of miR‐24 in T2DM and DFU group was significantly lower than in NC group (P < .05), and that in DFU group was significantly lower than in T2DM group (P < .01). Additionally, the level of miR‐24 significantly decreased in DFO group compared to non‐DFO group (P < .01). Moreover, it was negatively correlated with the amputation rate in DFU group (P = .043) and positively correlated with healing rate after 8 weeks (P = .036). The multivariate logistic regression analysis confirmed that a low expression of miR‐24 was an independent risk factor for DFU and DFO. The ROC curve analysis indicated that the AUC of miR‐24 for the diagnosis of DFU and DFO was 0.849 (95% CI, 0.618‐0.879, P < .001) and 0.782 (95% CI, 0.595‐0.813, P < .001). Thus, a decreased expression of miR‐24 of T2DM patients was closely related to the occurrence, development and prognosis of DFU and DFO, suggesting the use of miR‐24 as a potential biomarker for the prediction of DFU and DFO.