CODEO has made significant achievements over the years. Some of the accomplishments include the following:
- 2000: In its year of formation, CODEO recruited, trained and deployed 5500 of its members to observe the December 7 presidential and parliamentary elections, and the December 28 presidential Run-off elections in 137 constituencies throughout the country
- 2004: CODEO increased its membership from twenty-two to thirty-four groups and deployed more than 7000 observers nationwide
- 2008: CODEO deployed over 4000 observers for the December 7 polls and the December 28 presidential run-off. It also observed the residual Tain Constituency election
- 2012: CODEO deployed more than 4000 of its observers nationwide to observe the presidential and parliamentary elections
- CODEO assessed the Electoral Commission of Ghana as a model of successful governance institution-building in Africa.
- 2004: CODEO introduced innovations in domestic election observation with the introduction of systematic tracking of incumbency abuse and election violence. Similar activity was conducted in the 2008 and 2012 elections
- 2008: CODEO successfully introduced and used the Parallel Vote Tabulation (PVT) methodology for domestic election observation for the first time in Ghana to independently verify the accuracy of the results of the presidential polls
- 2012: CODEO combined PVT and statistical methodology to estimate election outcomes
- 2012: CODEO deployed over 650 trained pre-election observers to monitor the Biometric Voter Registration exercise, in districts, and prisons
- 2012: CODEO started post-election observation. It successfully monitored of the Supreme Court proceedings on the presidential election petition
- 2008, 2012 & 2016: CODEO has successfully deployed the Parallel Vote Tabulation (PVT) methodology in Ghana to independently verify the 2008, 2012 and 2016 Presidential Elections.
- 2002 to date: CODEO has observed local government elections and political party primaries of the major political parties in Ghana
- CODEO's expertise has been harnessed by observer groups from African countries such as Kenya, Liberia, Burundi, Nigeria, Togo, and Central African Republic. CODEO's PVT methodology experience has been shared with other domestic observer groups in African countries, including Nigeria, Kenya and Togo.
- CODEO is a founding member of the West African Election Observers Network (WAEON), a sub-regional network of the largest citizen election observation groups in 11 Anglophone and Francophone countries in West Africa. WAEON envisions a West Africa that is democratic, where governments are held accountable through regular and credible elections and citizens effectively participate in the electoral process through professional observation of elections.
- CODEO is a member of the Global Network of Domestic Election Monitors (GNDEM). GNDEM serves to bring together citizen observation efforts from around the world. As part of its effort to enhance citizen observation, GNDEM developed a "Declaration of Global Principles for Non-partisan Election Observation and Monitoring by Citizen Organizations" that provides best practices for citizen observation.
- CODEO provided technical support to civic election watchdog groups and other bodies in several African countries.
