Background: Several randomized trials performed in the era of doxycycline showed reduction in myocardial remodeling when compared with control therapy. Methods: This prospective study included 100 consecutive patients with first time acute anterior ST segment elevation myocardial infarction and left ventricular ejection fraction less than 40%.All patients underwent primary PCI and were divided into two groups; Group I who received bolus dose 100 mg of doxycycline immediately after PPCI then a maintenance dose 100 mg b.i.d for 7 days and group II who received standard treatment. Left ventricular end diastolic volume index (LVEDVI) was measured at baseline and six months by transthoracic echocardiography. Results: The 6-month LVEDVI significant decreased in the doxycycline group than in the control group [-13.2 ± 14.2 ml/m2 (26%) versus 7.4 ± 14.35 ml/m2(14%) respectively p= 0.001]. Left ventricular remodeling was reported in 60 % of all patients (42 % in group I versus 78 % in group II, P = 0.01). Conclusion: The result of current study suggests that doxycycline reduces the adverse LV remodeling in patients with acute anterior STEMI and LV dysfunction.