Missouri: Corporate Bylaws Adoption and Amendment Requirements

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.