Background: Small dense low-density lipoprotein (sd-LDL) has been demonstrated to be associated with cardiovascular diseases (CVD). The proposed atherogenic properties of hypoadiponectinemia might be mediated through increased sd-LDL. In this study, the associations of sd-LDL with cardiovascular and other complications of diabetes, and also with plasma levels of adiponectin, were investigated in diabetic patients. Methods: 173 patients, with documented type 2 diabetes mellitus, were enrolled in this cross-sectional study. Laboratory, anthropometric, and clinical characteristics were all determined. The presence of CVD, hypertention, and microalbuminuria were also evaluated. Homeostasis model assessment of insulin resistance was calculated. Results: Sd-LDL concentrations were significantly lower in patients with CVD than those without CVD (p = 0.020); and also lower in hypertensive patients relative to non-hypertensive ones (p - 0.008). Serum levels of adiponectin were significantly lower in patients with CVD (p<0.001), and hypertension (p = 0.002), compared with those without each of these complications. Sd-LDL and adiponectin concentrations were positively correlated (r - 0.36, p<0.001). Sd-LDL was also significantly associated with HbA1c (r = 0.24, p = 0.002). Conclusion: Our data suggest that decreased levels of adiponectin might be associated with developing complications of diabetes. This study did not provide any supportive results for the association of increased sd-LDL concentrations with CVD; neither for its association with other complications of diabetes.