Background: Perirenal fat is an important endocrine organ that produces and secretes bioactive cytokines and adipokines involved in the pathogenesis of cardiovascular diseases. The association of perirenal and pararenal fat tissue thickness (PPRFT) with subclinical atherosclerosis and myocardial function in patients with newly diagnosed type 2 diabetes mellitus (ND-T2DM) was investigated in this study. Methods: The study included 111 patients with ND-T2DM (59 males; mean age, 49.7±9.6 years) and 57 individuals without any disease diagnosis as the control group (23 males; mean age, 48.5±7.2 years). PPRFT and carotid intima-media thickness (CIMT) were measured using ultrasonography. Conventional parameters, including epicardial fat tissue (EFT) thickness, were measured using transthoracic echocardiography and myocardial velocities were measured using tissue Doppler echocardiography. Results: CIMT, EFT thickness, and PPRFT were higher in patients with ND-T2DM than in controls (p<0.001). While the E/A ratio was significantly lower in patients with ND-T2DM than in controls (p<0.001), the E wave deceleration time, and E/E′ septal and lateral ratios were significantly higher in the former (p<0.001, p<0.001, and p=0.002, respectively). PPRFT values were significantly correlated with CIMT and EFT thickness (ρ=0.490, ρ=0.517; p<0.001 and ρ=0.588, ρ=0.574; p<0.001, respectively) and negatively correlated with ejection fraction and mitral E/A ratio (ρ=–0.549, ρ=–0.530; p<0.001 and ρ=–0.512, ρ=–0.465; p<0.001, respectively). Conclusion PPRFT values measured using ultrasonography in patients with ND-T2DM are significantly associated with CIMT and EFT, which are indicators of subclinical atherosclerosis.