Background: In patients with inferior myocardial infarction (MI), involvement of the right chambers has a prognostic impact. The objective of this study was to evaluate the influence of left ventricular (LV) inferior wall MI in the right atrial (RA), and right ventricular (RV) longitudinal strain (LS) by 2D speckle tracking echocardiography (STE). Methods: 60 consecutive patients who underwent myocardial perfusion (MP) gated SPECT for chest pain were included. We studied 30 patients with LV inferior MI and 30 control subjects with normal MP. RV ejection fraction was measured by 3D transthoracic echocardiography, RV-free wall LS and RA reservoir, contraction, and conduit phases strain were analyzed by 2D speckle tracking echocardiography (STE). Results: The median age in the LV inferior MI was 65 (54–70) years, 27% had a transmural myocardial infarction and 47% had residual myocardial ischemia, most of them, mild (36.7%). RV-free wall LS (–26.1 vs –30.3, p 0.01), RA LS-reservoir phase (31.5 vs 56.2, p 0.01), and RA-conduit phase LS (12.5 vs 35, p = 0.01) were significantly lower in the LV inferior MI patients compared to control subjects. In a logistic regression model, the MI of the LV reduced the 3D ejection fraction of both ventricles, mitral regurgitation, and pulmonary hypertension were associated with a decrease in RV LS and RA LS. Conclusions: This study shows that RV free wall LS, RA peak strain (reservoir phase), and RA conduit phase strain were significantly lower in patients with LV inferior MI vs control individuals. Subclinical extension to the RV in the inferior MI of the LV and its role in the longitudinal strain of RA could be determined using speckle tracking echocardiography.