Myocardial Infarction is a major cause of death and disability worldwide. The incidence of coronary heart disease is high and second most cause of death after cancer. This prospective study conducted on 100 patients admitted with first attack of acute myocardial infarction in the department of Cardiology in Mymensingh Medical College Hospital, Mymensingh, Bangladesh from July 2012 to June 2013 who were observed 3 to 8 days of hospital stay without doing further echocardiography and evaluated the relationship between echocardiographic wall motion score index (WMSI) assessed within 24 hours of admission and in-hospital outcomes. Mean age was 53.24±10.17 years in WMSI <2 and 55.58±12.68 years in WMSI ≥2 groups; difference was statistically non-significant (p>0.05). In both groups, males were predominant sufferer. Male-female ratio was 3.55:1 and the difference was statistically non-significant (p>0.05). As a risk factor, smoking was significantly higher in both groups but the difference was not statistically significant (p>0.05) between groups. Hypertension was 34(49.28%) cases in WMSI <2 and 13(41.93%) cases in WMSI ≥2 group; difference was not statistically significant (p>0.05). Diabetes mellitus was 13(18.84%) cases in WMSI <2 and 16(51.61%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Dyslipidemia was 28(40.58%) cases in WMSI <2 group and 23(74.19%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Site of involvement of MI in WMSI <2 group were 39(56.52%) cases AMI (Anterior) and 30(43.48%) cases AMI (Inferior). In WMSI ≥2 group, AMI (Anterior) were 29(93.55%) and AMI (Inferior) were 02(6.45%). It revealed that AMI (anterior) was significantly higher in WMSI ≥2 group and AMI (Inferior) was significantly higher in WMSI <2 group. Heart failure class (Killip class) increases with the increasing of WMSI. In Killip class-I, 4(5.80%) were WMSI <2 and 01(3.23%) was WMSI ≥2 (p>0.05). In Killip class-II, 8(11.59%) were WMSI <2 and 02(6.45%) were WMSI ≥2 (p>0.05). In Killip class-III, 4(5.80%) were WMSI <2 and 13(41.94%) were WMSI ≥2 (p<0.05). In Killip class-IV, 2(2.89%) were WMSI <2 and 05(16.13%) were WMSI ≥2 (p<0.05) that was statistically significant. Arrhythmia was 14(20.29%) cases in WMSI <2 group and 13(41.94%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Death was 2(2.90%) cases in WMSI <2 and 07(22.58%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Early mortality rate was greater in patients with both WMSI ≥2 and a higher Killip's class. The higher the WMSI determined within 24 hours of admission, the worse the in-hospital outcome. Echocardiography is an affordable and readily available technique, which may be used to identify and stratify the risk following acute MI.