The secretariat is composed of a Secretary-General who is periodically elected by the assembly, and various divisions such as those for marine safety, environmental protection and a conference section.

[8] IMO held an emergency session of its council to deal with the need to readdress regulations pertaining to maritime pollution.

[8] The goal at hand was to develop an international agreement for controlling general environmental contamination by ships when out at sea.

During the next few years IMO brought to the forefront a series of measures designed to prevent large ship accidents and to minimise their effects.

It also detailed how to deal with the environmental threat caused by routine ship duties such as the cleaning of oil cargo tanks or the disposal of engine room wastes.

[10] As such, sea transportation is one of few industrial areas that still commonly uses non-metric units such as the nautical mile (nmi) for distance and knots (kn) for speed or velocity.

Throughout its existence, the IMO has continued to produce new and updated conventions across a wide range of maritime issues covering not only safety of life and marine pollution but also encompassing safe navigation, search and rescue, wreck removal, tonnage measurement, liability and compensation, ship recycling, the training and certification of seafarers, and piracy.

In 1983, the IMO established the World Maritime University in Malmö, Sweden and also facilitated the adoption of the IGC Code.

These amendments gave rise to the International Ship and Port Facility Security (ISPS) Code, which went into effect on 1 July 2004.

The IMO headquarters are located in a large purpose-built building facing the River Thames on the Albert Embankment, in Lambeth, London.

[13] The front of the building is dominated by a seven-metre high, ten-tonne bronze sculpture of the bow of a ship, with a lone seafarer maintaining a look-out.

[13] The previous headquarters of IMO were at 101 Piccadilly (now the home of the Embassy of Japan), prior to that at 22 Berners Street in Fitzrovia and originally in Chancery Lane.

One broad topic it deals with is the effect of the human element on casualties; this work has been put to all of the sub-committees, but meanwhile, the Maritime Safety Committee has developed a code for the management of ships which will ensure that agreed operational procedures are in place and followed by the ship and shore-side staff.

[20] Prior to 2013 there were nine Sub-Committees as follows: To become a member of the IMO, a state ratifies a multilateral treaty known as the Convention on the International Maritime Organization.

These include Afghanistan, Andorra, Bhutan, Burkina Faso, Burundi, Central African Republic, Chad, Eswatini, Laos, Lesotho, Liechtenstein, Mali, Niger, Rwanda, South Sudan, Tajikistan and Uzbekistan.

Memoranda of Understanding (protocols) were signed by some countries unifying Port State Control procedures among the signatories.

[2] Conventions, Codes and Regulations: Recent initiatives at the IMO have included amendments to SOLAS, which among other things, included upgraded fire protection standards on passenger ships, the International Convention on Standards of Training, Certification and Watchkeeping for Seamen (STCW) which establishes basic requirements on training, certification and watchkeeping for seafarers and to the Convention on the Prevention of Maritime Pollution (MARPOL 73/78), which required double hulls on all tankers.

[49] IMO has also served as a key partner and enabler of US international and interagency efforts to establish maritime domain awareness.

The First Intersessional Meeting of IMO's Working Group on Greenhouse Gas Emissions from Ships took place in Oslo, Norway (23–27 June 2008), tasked with developing the technical basis for the reduction mechanisms that may form part of a future IMO regime to control greenhouse gas emissions from international shipping, and a draft of the actual reduction mechanisms themselves, for further consideration by IMO's Marine Environment Protection Committee (MEPC).

[51] Nonetheless, there has been widespread criticism of the IMO's relative inaction since the conclusion of the Paris conference, with the initial data-gathering step of a three-stage process to reduce maritime greenhouse emissions expected to last until 2020.

[55] In December 2023 the IMO adopted a resolution targeting "dark fleet" tankers that form a risk by undertaking illegal and unsafe activities at sea.