The holy has referred to the conditions of the Hour in the verse 18 of chapter Mohammad. By the conditions of the Hour is meant the events that happen before resurrection or the appearance of Imam ahdi (a). Commentators of fariqain, relying on the sayings of the Prophet and Imams, have paid much attention to the subject. Though the expression of the conditions of the Hour has been used frequently in Islamic sources, there can be found many cases of ambiguty between the signs of resurrection and those of Imam`s appearance. An attempt has been made in this paper to distinguish these signs with reliance on Quranic verses, traditions and analyzing the content with regard to the cases and Sunni and Shiite commentaries.