Background: The data about cardiovascular (CV) changes in patients with asymptomatic primary hyperparathyroidism (PHPT) are scarce. Aim: The aim of this study is to compare cardiac structure and functions in patients with asymptomatic PHPT and controls by using tissue Doppler echocardiography. Subjects and methods: Thirty-eight patients with asymptomatic PHPT and 31 sex-and age-matched controls with similar cardiac risk factors were evaluated. Results: There was no significant difference in ejection fraction (EF) between the patients and the controls [64 +/- 5.95 vs 62 +/- 3.25% (p=0.094)].Left ventricular mass index (LVMI) was significantly higher in patients than controls [105.96 (66.45-167.24) vs 93.79 (64.25-139.25) g/m(2), p=0.014]. There was a significant correlation between LVMI and serum calcium (Ca) (r=0.240, p < 0.005). Myocardial performance index (MPI) was significantly higher in patients than controls [0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p < 0.001]. There was positive correlation between the MPI and serum Ca levels (r=0.505, p < 0.001), parathyroid hormone (PTH) levels (r=0.464, p < 0.001) and LVMI (r=0.270, p < 0.005). When the normotensive patients and controls were evaluated, the difference between the groups remained statistically significant considering LVMI and MPI [109 (66.45-1067.24) g/m(2) vs 94.17 (64.25-75.10) g/m(2), p=0.03; and 0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p < 0.01, respectively]. There were significant correlations between MPI and Ca (r=0.566, p < 0.001), and PTH (r=0.472, p < 0.001). Conclusions: Our study results showed that cardiac morphology and diastolic functions are altered in the patients with asymptomatic PHPT. High serum PTH and Ca levels may have an impact on these CV changes. Whether these subtle CV changes would affect cardiac systolic functions and mortality in patients with asymptomatic PHPT should be investigated in further prospective studies.