Banks, as the most important institutions in money market, have a vital role in financing manufacturing, service-delivery and trade projects. As a result of a set of problems in economy of Iran, nowadays banking system is faced with financing problems itself. A common method in solving this problem is to use bank's assets backed security. Applying this instrument is common in conventional banking, but it is not yet widely used in Islamic banking, for example in Iran.As a result of Security Market Law in 2005 (1384) and its amendment in 2009 (1388 in Iran) designing and offering of new securities became accepted. Now banks can finance themselves in capital market through designing and offering new financial instruments.This article, which it's purpose is to introduce such an instrument, is composed of two sections. In first section, after reviewing history of bank assets' securitization in conventional and Islamic banking, we explained the goals, performance and pathology of securitization in banks. Then, we designed a compatible financial instrument for securitization of bank assets for Iranian banks. Such an instrument should comply with some conditions: first, it should be acceptable in Fiqh. Second, it should meet the terms of Monetary and Financial Law of Iran. Third, bearing in mind the role of financial instruments in creating the recent financial crisis, it must not create crisis.