Background Although aortic valve replacement (AVR) when successfully performed boasts low mortality rates in selected patients, prosthesis-patient mismatch (PPM) can be found in the majority of these individuals. Limited research is available supporting the benefit of two-dimensional speckle tracking echocardiography (2D-STE) in patients with severe PPM. This study sought to assess myocardial strain using 2D-STE to determine the relationship between subclinical left ventricular (LV) dysfunction and aortic PPM in patients undergoing AVR with preserved LV ejection fraction. Material and methods We retrospectively examined all consecutive patients with isolated AVR who presented to our center from 2005 to 2018. The data of 1086 patients were analyzed. Severe PPM was defined as an indexed effective orifice area of 0.65 cm(2)/m(2) or less. As a result of the detailed assessment, 54 patients meeting the eligibility criteria were included in the study. Baseline data were collected and compared between the two groups of patients with severe PPM (n = 27) and those with normofunctional aortic prosthesis valve as a control group (n = 27). All patients underwent baseline echocardiography. Global longitudinal strain (GLS) and global circumferential strain (GCS) were evaluated by 2D-STE. Results When compared with controls, patients with severe PPM had significantly decreased GLS (18.6 +/- 2.9 vs. 21.4 +/- 2.1; p < 0.01) and GCS (17.2 +/- 3.6 vs. 21.7 +/- 2.1; p < 0.01) values. Conclusion In addition to standard clinical and echocardiographic parameters, GLS and GCS suggest subclinical dysfunction and have incremental value in patients with severe PPM.