AIMS: To investigate the associations between Lp(a), Apo A1, Apo B, and Apo B/Apo A1 ratio with micro- and macrovascular complications of diabetes. METHODS AND RESULTS: In this case-cohort study, 1057 patients with type 2 diabetes (T2DM) were followed in the diabetes clinic of Vali-Asr Hospital from 2014 to 2019. The association between serum Lp (a) and apolipoproteins with cardiovascular disease (CVD), neuropathy, and nephropathy were assessed by using binary regression analysis. The ROC curve analysis was used to evaluate the predictive properties of proteins. Youden index was used to calculate cutoff values. Among patients with T2DM, 242, 231, and 91 patients developed CVD, neuropathy, and nephropathy, respectively. The serum Lp (a) level was positively correlated with the development of all three. (P-values = 0.022, 0.042, and 0.038, respectively). The Apo A1 level was negatively correlated with nephropathy. Among the biomarkers, Lp(a) had the highest AUC for prediction of CVD, neuropathy, and nephropathy. Calculated cutoff values of Lp(a), and Apo A1 levels were higher than the standard cutoff values. CONCLUSION: Serum level of Lp(a) is a predictor for CVD, neuropathy, and nephropathy. Based on the calculated cutoff values in patients with T2DM, we should consider diabetic complications at higher levels of Lp(a).