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 acute anterior ST segment elevation myocardial infarction and left ventricular ejection fraction less than 40%.all patients under went 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. Echo left ventricular end diastolic volume index were determined at baseline and six month. Results: primary end point was reported The 6-month changes in % LVEDVI were 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], and left ventricular remodeling which was was reported in 60 % of all patients (42 % in group I versus 78 % in group II, P = 0.011). Conclusion: the result of current study suggest that doxycycline reduces the adverse LV remodeling for comparable to standard treatment in patients with acute anterior STEMI and LV dysfunction.