Corporate Bylaws Adoption and Amendment Requirements in Missouri

At a glance

Requirements one by one

Original bylaws have two actor routes

Mo. Rev. Stat. § 351.290 permits the directors to adopt the original bylaws. It does not state a general deadline or a stand-alone command that every ordinary corporation must adopt them.

When the articles do not name the first directors, § 351.080 gives the incorporators a different route. They may adopt the original bylaws by a unanimous vote at a meeting or by unanimous written consent, and they name the first board at the same time. The first board then holds its organization meeting as soon as convenient, inside or outside Missouri, at the call of a majority of the directors.

Mo. Rev. Stat. § 351.340 allows any board action that may be taken at a meeting to be taken instead by unanimous written or electronic consent. The secretary must file those consents with the board minutes. Missouri does not separately say that original bylaws must be adopted at the organization meeting.

Later power defaults to shareholders, subject to the articles

Under Mo. Rev. Stat. § 351.290, shareholders hold the power to make, alter, amend, or repeal bylaws unless and to the extent the articles vest that power in the board. This is an articles-based allocation: original board adoption does not by itself prove that the board owns ordinary later amendment power.

The same section allows bylaws regulating and managing corporate affairs only when they are consistent with law and the articles. Mo. Rev. Stat. § 351.385 repeats that hierarchy as a corporate power to make and alter bylaws for administration and regulation of corporate affairs.

Higher-vote provisions can displace statutory defaults

Mo. Rev. Stat. § 351.270 makes a shareholder-adopted bylaw controlling when it requires a greater share vote or concurrence for a shareholder action than Chapter 351 otherwise requires. Shareholders may act without a meeting under § 351.273 only through written consents signed by every shareholder entitled to vote on the matter.

For the board, § 351.325 allows the articles or bylaws to require more than a majority of the full board for a quorum or more than a majority of directors present for board action. The surveyed sections do not add an actor-of-origin or same-or-greater-vote lock specifically for later amendment of that board provision, so the ordinary § 351.290 allocation still matters.

The records statute does not specifically list bylaws

Mo. Rev. Stat. § 351.215 requires correct and complete account books, board and shareholder minutes, officer information, and specified share records. It allows each shareholder access to the company's books at proper times under regulations prescribed by the bylaws, but its express record list does not name a retained copy of the bylaws.

The current Chapter 351 provisions surveyed here state no general signature, acknowledgment, notarization, certification, or Secretary of State filing step for ordinary bylaws. A filed corporate document or a certification block in a private form should not be treated as proof of a statutory bylaw formality.

Statutory close corporations use a special substitute

Mo. Rev. Stat. § 351.810 allows a statutory close corporation to omit bylaws when provisions required by law to be in bylaws instead appear in the articles or a shareholder agreement authorized by § 351.800. That agreement is a written agreement of all shareholders and ordinarily requires all-shareholder written approval for amendment unless the agreement says otherwise.

If statutory-close status ends while the corporation has no bylaws, § 351.810 requires immediate adoption under § 351.290. That special rule does not convert every ordinary corporation's original-bylaw power into an unstated formation deadline.

Section 351.290 also permits the board to adopt emergency bylaws for an attack on the United States or a nuclear or atomic disaster. Consistent regular bylaws remain effective during the emergency, and the emergency bylaws cease when the emergency ends.

What trips people up

The first-board organization meeting must be held as soon as convenient, but the statute does not expressly make adoption of bylaws one of that meeting's required acts. Do not turn the organization-meeting timing into a bylaw filing deadline.

The board's authority to adopt the original bylaws is not the same as ordinary later amendment authority. The articles must vest later power in the board to displace the shareholder default to that extent.

Section 351.215 lets bylaws prescribe regulations for shareholder access to company books. It does not say that ordinary bylaws themselves must be filed with the state or kept at a specifically named office.

Common questions

Can Missouri incorporators adopt the original bylaws?

Yes, when the articles do not name the first directors. The incorporators must act unanimously at a meeting or by unanimous written consent under § 351.080.

Can the board amend the bylaws merely because it adopted them first?

Not on that fact alone. Section 351.290 places later power in the shareholders unless and to the extent the articles vest it in the board.

May shareholders approve a bylaw without holding a meeting?

Yes, but § 351.273 requires written consents signed by all shareholders entitled to vote on the subject. The consents must be filed with the shareholder meeting minutes.

Must ordinary Missouri bylaws be filed with the Secretary of State?

The current Chapter 351 provisions surveyed for this page state no general public-filing requirement for ordinary bylaws.

Statutes and sources

• Mo. Rev. Stat. § 351.080 \u2014 conditional incorporator adoption and the first-board organization meeting. Official text, accessed August 21, 2026.
• Mo. Rev. Stat. § 351.290 \u2014 original director adoption, later power, content limits, and emergency bylaws. Official text, accessed August 21, 2026.
• Mo. Rev. Stat. §§ 351.270, 351.273, 351.325, and 351.340 \u2014 higher votes and meetingless shareholder or board action. Official Chapter 351 index, accessed August 21, 2026.
• Mo. Rev. Stat. § 351.215 \u2014 corporate records and shareholder access. Official text, accessed August 21, 2026.
• Mo. Rev. Stat. §§ 351.800 and 351.810 \u2014 statutory-close shareholder agreements and the no-bylaws substitute. Official Chapter 351 index, accessed August 21, 2026.