Background and Aim: In present era, one of the new and important issues in the field of medical issues is the treatment of infertility in couples and having baby by artificial fertilization methods. One of the new methods in this field is surrogacy, so that the applicant rents another woman's uterus to spend the period of carrying her fetus so that the fetus is born from her. Materials and Methods: This descriptive-analytical study seeks a well-reasoned juridical answer for the validity of surrogacy contracts. So by using the library resources, it examines the subject of research in jurisprudential books and also adaptes the conditions for surrogacy validity such as determining the benefit of the LEASEd action, the existence of the intended benefit and the permission to receive the rent and … with surrogacy and finaly its selected defining and declaratory law is expressed. Conclusion: This article examines the argumentative and jurisprudential issues related to this issue and jurists’ views and it concludes that there is a connection between reproduction and marital relationship in Islam. Therefore, it is not possible to using uterus of another woman to have children, and renting a uterus for this purpose will be void. The surrogacy contracts and receiving wage will be valid and permissible only in the cases of artificial fertilization permission, such as the use of the uterus of a second spouse or temporary spouse.

The rent for ownership agreement is an agreement, which its virtue, the object of transaction is rented provided that the ownership of the object of transation to be trasferred to tenant in case that all conditioins of agreement and installments of the rent paid by tenant. This agreement is among the legal instituions that although has no jurisprudence background and is not mentioned in eivil law, but is accepted in all of our legal sestem. The reason may be that despite of similiarities and differences with similar legal instituions, it has some advantages toward them, e.g the legla indentity of thes agreement is rent and it is differen with sale on installments, optional sale and suspended immediately after the agreement but in the rent for ownership will not be obtained for buyer before obtaining suspender and having and holding the object of sale is not legal, but in the rent for ownership toward the interest of premise and is correct. So we conclude that the condition of ownership in the rent for ownership is a resull condition. General speaking, the agreement of the rent for owership wich is a necessary, changeable and ownership agreement an can be on house,land or and other goods in various sectors like agriculture and servicess and the general principles on the parties of agreement is depending on the LEASE agreement.

The two parts of a LEASE contract cannot always assign the period of LEASE. Sometimes it isn't mentioned any period in contract but they assert the smallest unit of time for assignment of the rental. Therefore the civil low makes reputable the LEASE contracts that the period of rent is left unsaid in them for the same smallest unit of time. In spite of that the legal spirit of this agreement isn't so distinct to accredit the contracts lacking of period.In this paper it has been tried to study such contracts and at same times the legal spirit of these agreement has been investigated.

This paper focuses on a comparison between LEASE and purchase while analyzing the effective features in making a decision on and selecting each. To do this, elements like cash outlay, the risk of absolescene, the abolition of LEASE and the possibility of cash allocation for profitable uses are dealt with. Besides, to present a concise comparison, different alternatives of purchase such as financing through borrowing and financing by means of installment sale are explained and exemplified by conditional sales and chattel mortgage, respectively. Cash circulation, tax factor, the omission of operations expenses, scrap and present values, as well as relevant problems in LEASE and purchase are also discussed.

LEASE of premises is a contract have a lot of application in society.in accordance with existance of some practical results on division between translative and promissory theory of the LEASE: such as possibility of possession of interests to others by LEASE holder analysis of the translative theory-that is an accepted theory by famous Islamic jurisprudents and civil law- is nessacery.

Imāmī jurists have considered the agreement of the couple to establish a marriage bond for a limited period as a temporary marriage and one of the types of marriage, which can be considered as a kind of contract based on the exchange of "marriage portion" for "sexual exploitation", due to the trends in some exchange rulings. The fact that "marriage portion" and "duration" are essentials in temporary marriage has caused a group of Imāmī jurists to consider it as an example of a "LEASE contract". Assuming a temporary marriage as rental has caused this contract to face important jurisprudential and moral challenges, such as the degradation of the status of women. The findings of this study, which was performed by analytical and descriptive methods and based on library sources, show that despite some apparent similarities between temporary marriage and rent in some elements and rulings, the nature of temporary marriage is the couple's agreement on married life in a certain period and there is no exchange between the sexual productivity of the wife for the payment of the marriage portion by the husband for a certain period of time.

In all contracts, the first principle is based on necessity, but use of this principle by common excuse can be abolished. The common excuse against the special excuse is a barrier out of parties will which generally prohibits the obligation of contract or in some cases like LEASE contract it can hamper the vindication of benefits. The prohibition of the vindication of benefits by common excuse depending on the time of appearance would had been effected because common excuse can be appear in various times, because the common excuse can be happened sometimes before bill of subject of hire and sometimes immediately after that and sometimes with an interval after bill maybe before any exploitation of benefits or during the exploitation or at the end of the that. This research has investigated these aspects especially related to LEASE contract.

One of the current authorities in necessary contracts, including LEASE contract, is the authority of loss. The loss that is based on the civil law and the most jurists' viewpoints is the loss that exists during the conclusion of the contract (simultaneous loss), and the loss that occurs after the conclusion of the contract and at the stage of fulfilling the obligations has received less attention from the experts. Since the LEASE contract is one of the contracts, in which the obligations of the parties are fulfilled over time and since all the obligations are not considered fulfilled only due to landlord withdrawing from the object of the LEASE, it is important to examine the authority of loss occurring in the LEASE contract, because it is possible that any change in circumstances may make the parties lose their balance after or at the time the contract has been concluded. Based on arguments such as the no-harm principles and the implicit condition, as well as the intellectuals' viewpoints and finally compulsion, the author of this paper claims that the occurrence of loss during the conclusion of the LEASE contract like the existence of loss at the time of concluding the contract can cause the right of authority for the party that has lost something in the contract. Such a solution would both help the efficiency of the current trade and economic system and it is in line with the principles accepted by the Iranian legal system.