Coronary artery tortuosity (CAT) is a common finding in coronary angiography, and is defined as three fixed bends during both systole and diastole in at least one epicardial coronary artery, with each bend showing a 45 degrees change in vessel direction. The impact of CAT on the myocardial deformation has not been completely evaluated using 3D-STE. As a result of this, we aimed to assess the effects of CAT on LV functions using 3D-STE in the present study. Eighty-two patients with CAT and 80 age- and gender-matched controls who proved to have normal coronary angiograms were enrolled into the study. 3D-STE was performed and LV-GLS, LV-GCS, LV-GAS, and LV-GRS were obtained for every patient after coronary angiography. The LV-GLS was significantly depressed in the CAT ( +) group than in the control group (p = 0.001). ROC analysis was performed to find out ideal LV-GLS cut off value to predict the presence of CAT. A LV-GLS value of > - 17 has 81.3% sensitivity, 56.7% specificity to detect the presence of CAT. The present study is the first to focus on the assessing LV myocardial functions in patients with CAT by 3D-STE. CAT has a considerable negative effect on LV myocardial longitudinal deformation as evaluated by 3D strain parameters. Our results support that patients with CAT may have subclinical LV longitudinal deformation abnormalities even though they are apparently healthy.