Exhibit 5 Brega & Winters P.C. Attorneys at Law Wells Fargo Center, 1700 Lincoln Street, Suite 2222 Denver, Colorado 80202 October 24, 2002 Rentech, Inc. 1331 17th Street, Suite 720 Denver, Colorado 80202 Re: Registration Statement No. 333-85682 on Form S-3/A Amendment No. Two Gentlemen: This firm has represented Rentech, Inc., a Colorado corporation (the Company), in connection with the proposed offering by selling shareholders of up to 8,672,986 shares of its common stock, $.01 par value, including shares of common stock underlying its convertible promissory notes and stock purchase warrants and stock options to purchase common stock, pursuant to a registration statement on Form S-3/A. In connection with such representation, we have reviewed the Company's articles of incorporation, bylaws, minute books and the applicable laws of the state of Colorado. Based on such review, we are of the opinion that the shares of common stock issued or to be issued pursuant to this registration statement are fully paid, validly issued and non-assessable. We hereby consent to the reference to our firm under the heading "LEGAL OPINIONS" in the registration statement on Form S-3/A and the related prospectus and to the filing of this opinion with the Securities and Exchange Commission as an exhibit to the registration statement. Very truly yours, /s/ BREGA & WINTERS P.C.