The aim of this study is to examine the role of the Uzbek agar (if) conjunction in different sentence types from a syntactic and functional perspective. There is no independent marker of Turkish origin at the beginning of the sentence that marks the condition. In Uzbek, the conditional meaning can be marked with inflectional elements such as {-ganda}, {-ar ekan} as well as the {-sa} morpheme. Agar can be used in all sentence types containing this meaning, mostly as a intensifier of the conditional meaning. Although it is usually at the beginning of the non-finite sentence, it can also occur in different positions. With its this usage and function, agar is a lexical copy in Uzbek. Since such sentences are Turkish type, removing agar from the sentence, as a condition intensifier, does not cause any loss or change in the sense. However, the situation of agar particle draws attention especially in oath sentences. Such sentences require addressing the subject in terms of language contacts. Because the Uzbek oath sentences formed with agar, coincide with the form of the Persian oath sentences. In such sentences, it is seen that a non-Turkish type of sentence structure is copied from Persian with its syntactic and functional features in relation to the agar conjunction. It has also been found in the literary texts, that the condition is directly marked with agar. Such sentence structures are the copies of Persian sentence structures that appear in Uzbek through literal translation. This study deals with the sentence types formed with the agar conjunction, its functional and syntactic features and the role of language relations in the sentence types. The material of the study consists of Uzbek novels chosen from different authors and years.