The Criminal Procedure Code No. 23 of 1971 replaced the Baghdad Procedure Code of 1919. It was modelled on the Egyptian Criminal Procedure Code No. 150 of 1950, which itself was based upon the Napoleonic Codes adopted in Egypt in the late 19th Century.

It has been amended on a number of occasions. For example, the Public Prosecutor Law No. 159 of 1979 replaced paragraphs 30 to 38 of the Criminal Procedure Code and made other amendments. In the period up to 2003, there were over a dozen laws specifically entitled ‘Amendment to the Criminal Procedure Code’. There were also over 20 Revolutionary Command Council Resolutions which amended some aspect of criminal procedure often without specifically amending the original text – most prominently RCC Resolution No. 104 of 1988 which altered the mechanism of appeal in misdemeanour cases. Most of these RCC Resolutions are still in effect.

CPA Memorandum 3, in its original version, states that it came into force upon the date of signature on 18 June 2003. It was published in the Official Gazette, issue 3978. A revised version of the Memorandum, which is the one available on the CPA Archive website, states that it came into force upon the date of signature on 27 June 2004, 5 days before the transfer of authority to the Iraqi Interim Government. This does not appear to have been published in the Official Gazette. When subsequent revisions have been made by the Iraqi legislature, reference has only been made to the original memorandum. Below the references are to the original published version of Memorandum 3.
In its preamble, Memorandum 3 notes “the deficiencies of the Iraqi Criminal Procedure Code with regard to fundamental standards of human rights” but does not states what these deficiencies are.
Section 3 states that “All provisions of the Iraqi Law on Criminal Proceedings of 1971, as amended (hereinafter “the Procedure Code”), shall continue in force unless expressly modified by this Memorandum.”
Section 4 sets out the suspension and amendment of various provisions as follows:
“The following provisions of the Procedure Code shall be suspended and or amended:
a) In paragraph 61 (c) delete the word “may” and insert the word “must”.
b) In paragraph 70 delete the words “As far as possible”.
c) In paragraph 123 add the following; “(b) Before questioning the accused the examining magistrate must inform the accused that:
i) he or she has the right to remain silent and no adverse inference may be drawn from accused’s decision to exercise that right;
ii) he or she has the right to be represented by an attorney, and if he or she is not able to afford representation, the Court will provide an attorney at no expense to the accused;
c) The examining magistrate or investigator must determine if the accused desires to be represented by an attorney before questioning the accused. If the accused desires an attorney the examining magistrate or investigator shall not question the accused until he or she has retained an attorney or an attorney has been appointed by the Court.”
d) Paragraph 136 is hereby suspended. [Subsequently, Interim Prime Minister Allawi reinstated 136(b). Transitional Prime Minister Jaffari suspended it again when he came to office, but then reinstated it once more. The Council of Representatives passed a law on 18 September 2007 amending 136(b) and another law on 8 October 2007 revoking 136(b) but these laws have never been published in the Official Gazette and therefore 136(b) remains in force. It was reported in May 2009 that the Prime Minister had suspended the operation of the law in part. See more here]
e) In paragraph 144 (a) delete the words” at a rate of no less than 10 dinars and no more than 50 dinars, with the cost borne by the state treasury.”, and in 144 (b) delete the words “of no more than 50 dinars”.
f) In paragraph 168 (b) delete the words “via the court”.
g) In paragraph 179 delete the words “A refusal to answer will be considered as evidence against the Defendant”
h) In paragraph 184 (a) delete the word “must” and insert the word “may”.
i) In paragraph 199 (a) delete the words “based on permission from the Minister of Justice”.
j) In paragraph 213 (c) delete the words “and if there is no other evidence which proves it to be a lie.”
k) In paragraph 218 delete everything in the paragraph after the word “coercion” where occurring for the first time.
l) Paragraph 221 is hereby suspended.
m) Paragraphs 285-293 are hereby suspended.
n) In paragraph 298 delete the words “by one half of one dinar” wherever occurring.
o) In paragraph 299 (b) delete the words “one day for each one half of one dinar outstanding” and insert in place the words “reduced proportionally to the amount outstanding”.
p) Paragraph 306 is hereby suspended.
q) In paragraph 320 delete the words “and with the payment, within a specified period, of surety of not less than 20 dinars and not more than 200 dinars.
r) In paragraph 324 delete the words “of no less than 50 dinars and not exceeding 500 dinars”.
s) Paragraph 371 (b) is hereby suspended.”
Section 5 introduced the right of a subject upon arrest to be informed of the right to silence and to consult an attorney. Section 8 introduced the right to a publicly funded attorney. Sections 6 and 7 set out the position of suspects detained by Multi National Forces (rather than the Iraqi Police).

CPA Order 31 (which states that it came into force upon the date of signature on 9 October 2003) modified the Penal Code 111 of 1969 and the Criminal Procedure Code.
Section 4, with reference to increased penalties imposed for wrecking, destroying or otherwise damaging water, electricity, or oil installations or other public utilities contrary to Penal Code Paragraph 353(1) states, “Persons convicted of committing these offenses shall not be eligible for Conditional Discharge as set forth in Paragraph 331 of the Criminal Proceedings Law.”
Section 6 states,”Notwithstanding the bail provisions contained in Paragraph 109 of the Criminal Proceedings Law No. 23 of 1971 the reviewing judge may order a person suspected of committing an offense punishable by life imprisonment to be held without bail until trial.”