The long-term prognostic importance of hyperkinesia is unknown following an acute myocardial infarction (AMI). The American Society of Echocardiography recommends that hyperkinesia should not be included in calculation of wall motion index (WMI). The objective of the present study was to determine if hyperkinesia should be included in WMI when it is estimated for prognostic purposes following an AMI. Six thousand, six hundred seventy-six consecutive patients were screened 1 to 6 days after AMI in 27 Danish hospitals. WMI was measured in 6,232 patients applying the 9-segment model and the following scoring system: 3 for hyperkinesia, 2 for normokinesia, 1 for hypokinesia, 0 for akinesia, and -1 for dyskinesia. All patients were followed with respect to mortality for at least 3 years. WMI was calculated in 2 different ways: 1 including hyperkinetic segments (hyperkinetic-WMI) and the other excluding nonhyperkinetic segments (nonhyperkinetic-WMI) by converting the hyperkinetic segments to normokinetic segments. Hyperkinesia occurred in 736 patients (11.8%). WMI was an important prognostic factor (relative risk 2.49; p = 0.0001) for long-term mortality together with heart failure, history of hypertension, angina, or diabetes, previous AMI, age, thrombolytic therapy, arrhythmias, and bundle branch block. In a multivariate analysis including nonhyperkinetic-WMI, hyperkinesia was associated with a relative risk of 0.84, which was statistically significant (confidence intervals 0.74 to 0.96; p = 0.01). When hyperkinesia was included, both in WMI (hyperkinetic-WMI) and as an independent variable, no additional prognostic information (relative risk 0.93; p = 0.26) was obtained. An echocardiographic evaluation shortly after an AMI gave important prognostic information, especially if the information concerning hyperkinesia was included. If WMI is used for prognostic purposes, hyperkinesia should be included in calculation of the index.