Obligation relationship results from a particular legal circumstance. In current Polish legislation, the legislator provides neither for a systematized catalogue of sources of obligations, nor for a compiled version thereof. An obligation can result not only from a legal basis, but also from case law or administrative decisions. Under substantive civil law, obligations can be divided into unjust enrichments, unlawful acts and acts in law. In addition, acts in law can take form of unilateral acts or form of agreements which are discussed in this article. Brokerage agreement, which is an innominate contract not specified by the Polish legislator, also constitutes a contractual obligation. This type of agreement is subject of constant evolution in the insurance law doctrine, by becoming a kind of obligation which takes shape and assumes its unique features, distinguishing it from other agreements. The author makes an attempt to define the essential aspects of a contract concluded between subjects seeking insurance protection and professional insurance intermediaries, and to determine whether this agreement requires the standard of the utmost good faith. Having applied dogmatic and empirical legal methods, he considers the legitimacy of demands for treating this obligation as a nominate agreement.