Aim: Primary hyperparathyroidism (PHPT) is an endocrine disease that poses a risk for cardiac arrhythmias. Atrial electromechanical delay (EMD) has been known as an early marker of atrial fibrillation (AF). This study aimed to evaluate the atrial EMD in PHPT. Methods: Fifty PHPT patients (45 females, 5 males) aged 30-75 years and 38 controls (35 females, 3 males) aged 31-73 years were included in the study. Atrial EMD parameters were measured by using tissue Doppler imaging (TDI). Inter-atrial EMD was calculated as the difference between PA lateral and PA tricuspid, intra-atrial EMD was calculated as the difference between PA septum and PA tricuspid, and left-atrial EMD was calculated as the difference between PA lateral and PA septum Results: Atrial EMD parameters (PA lateral, PA septum, PA tricuspid) significantly increased in PHPT group compared to control group (p<0.001, for all). Also, inter-atrial and intra-atrial EMD were higher in PHPT group compared to control group (p<0.001, for all). In correlation analysis, calcium was well associated with PA lateral (r=0.748, p<0.001), PA septum (r = 0.720, p <0.001), inter-atrial EMD (r = 0.670, p <0.001) and intra-atrial EMD (r = 0.616, p <0.001). There was the same correlation relationship between PTH levels with PA lateral (r=671, p<0.001), PA septum (r=0.660, p<0,001), inter-atrial EMD (r=0.674, p<0,001) and intra-atrial EMD (r=0.732, p<0.001) Conclusions: Atrial EMD parameters were prolonged in PHPT. The measurement of atrial EMD parameters might be used to determine the risk of development of AF in PHPT