The concept of corrective feedback in learning a second language has gained more importance and it has been the subject of many researches during recent years. Therefore, considering some aspects that affect it such as when and how to correct, and also what types of corrective feedback are more preferable and effective is of crucial concern. The aim of this study is to find the most effective type of error correction (especially the best time: whether immediately or delayed) in the case of accuracy of Iranian EFL learners’ oral production. Thus, in order to investigate this study, 30 homogenous intermediate EFL learners were selected randomly (female) aged 13 to 30 from Tak English language institute in Dezful, Iran. The participants were divided into 2 groups of 15. For G1 errors were corrected immediately and for G2 with some delay, i.e. after finishing their speech during a term. At the end of the term, each student were asked to discuss one of the topics they have covered during the term, while their voices were recorded and transcribed later. Measures of accuracy were developed to examine the results. Data analysis indicated that both Immediate and Delayed Error Correction had positive effects on the accuracy of learners’ oral production. However, it was evident that although both types of CF were beneficial, the effects of Immediate Error Correction were larger than the other. In conclusion, regarding the specific purpose of language learning in a specific situation and classroom, it is recommended that teachers should be familiarized with all types of CF and then cautiously select the most appropriate one.