The aim of this study is to measure phosphate levels in AMI, compare and analyse its relation with left ventricular (LV) dysfunction and mortality. Serum phosphate was measured by kinetic assay method in 40 patients with acute myocardial infarction (AMI). Echocardiographic LV function was assessed in all and the patients were followed up for 30 days. Hypophosphatemia (< 2.5 mg/dl) was observed in 27% of AMI patients (11/40). These patients formed group 1 of our study. The rest 73% patients (29/40) with normal phosphate levels formed group 2. Mean Phosphate level in group 1 was 1.96 mg/dl (range 1.2-2.37) and mean ejection fraction (EF) was .35 (range .25-.50, p value < .001). Mean phosphate in group 2 was 3.693 (range 2.6-6.00) and mean EF was .53 (range .38-.65, p value < .001). In hospital mortality of the group 1 was 28% (3/11) while in group 2 was 6.8% (2/29). We conclude hypophosphatemia in AMI is associated with LV dysfunction which results in increased 30 day mortality.