Legislation approved by the 1971 General Assembly (H.B. 156) provides for preintroduction of bills beginning December 1 preceding the opening of the assembly session and continuing up to, but not including, the first day of the session. Bills filed during the preintroduction period are automatically introduced and read the first time on the opening day of the session.

Bills may also be introduced by any senator or representative during the session. Bills may be written by the legislator or drafted by the staff of the Committee on Legislative Research at the request of a senator or representative. When introduced, a bill is assigned a number and read for the first time by its title by the Senate or House reading clerk. It then goes on the calendar for second reading and assignment to committee by the speaker of the House or the president pro tem of the Senate.

A public hearing before the committee to which a bill is assigned is the next step in the legislative process. Except in the case of some unusually controversial, complex or lengthy bills, the bill is presented by its sponsor and both proponents and opponents are heard in a single hearing. When hearings are concluded, the committee meets to vote and makes its recommendations. The committee may: (1) Report the bill with the recommendation that it "do pass"; (2) Recommend passage with committee amendments, which are attached to the bill; (3) Return the bill without recommendation; (4) Substitute in lieu of the original bill a new bill to be known as a committee substitute; (5) Report the bill with a recommendation that it "do not pass" or (6) Make no report at all.

After perfection and reprinting, the bill goes on the calendar for third reading and final passage. When the bill is reached in the order of business any member may speak for or against its passage but no further amendments of a substantive nature can be offered. At the conclusion of debate, a recorded vote is taken. Approval of a constitutional majority of the elected members (18 in the Senate and 82 in the House) is required for final passage.

Passage of the bill is then reported to the other house where it is again read a second time; referred to committee for hearing; reported by committee; and third read and offered for final approval. If further amendments are approved, these are reported to the originating house with a request that the changes be approved. If the originating house does not approve, a conference may be requested and members from each house are designated as a conference committee. Upon agreement by the conference committee (usually a compromise of differences), each reports to its own house on the committee's recommendation. The originating house acts first on the conference committee version of the bill. If it is approved it goes to the other house and upon approval there, the bill is declared "truly agreed to and finally passed." If either house rejects the conference committee report, it may be returned to the same or a newly appointed committee for further conferences.

Upon final passage, a bill is ordered enrolled. It is typed in its finally approved form, printed and the bills are closely compared and proofed for errors.

The governor has 15 days to act on a bill if it is sent to him during the legislative session; and 45 day if the legislature has adjourned or has recessed for a 30-day period.

If he signs a bill, it is returned to its house of origin with his message of approval, then delivered to the Office of Secretary of State. If the legislature is not in session, it is delivered directly to the Office of Secretary of State.

If the governor vetoes a bill, it is returned to the house of origin with his objections. A two-thirds vote by members of both houses is required to override a governor's veto.

If any bill shall not be returned by the governor within the time limits prescribed by Article III, Section 31 of the Missouri Constitution it shall become law in the same manner as if the governor had signed it.

The secretary of state preserves the finally typed copy of the law. All the laws are bound together in one volume at the close of each session and seldom are seen unless some question arises. Prior to binding of the laws, the secretary of state publishes annually a volume of "Laws of Missouri", which is distributed to members of the General Assembly, state officials and other interested persons.

The general statute laws are revised by the revisor of statutes in the Office of the Committee on Legislative Research, digested and promulgated. These are known as the Revised Statutes of Missouri. Under legislation, the Committee on Legislative Research also publishes annual supplements to the statutes to include changes in laws since the last revision.