The importance of election security has been significantly increased in Nigeria's voting process. This is due to the fact that the nation's electoral contests are often characterised by violence and fraud. This can be comprehended due to the state's dual function as both a regulator and the predominant participant in the economy. Accusations of professional misconduct by security officers assigned to ensure the safety and peacefulness of elections have frequently had a negative impact on the integrity and credibility of elections in the Fourth Republic of Nigeria. The responsibility of security organisations to safeguard electoral security before, during, and after elections has consistently been a matter of concern. This essay aims to establish a correlation between the political bias of security agencies and the integrity of elections in Nigeria's fourth republic and subsequent periods. The methodology of this study is grounded in Marxian post-colonial state theory and employs a qualitative approach for data collection and analysis. The research asserts that security agencies adopted a biassed stance before and during elections, compromising the credibility of electoral results. The policy implications include the fact that security institutions that are impartial and free from political influence are necessary for guaranteeing fair elections. It is essential to enhance the professionalism of these organisations, as it is an absolute requirement rather than an optional policy decision. It is advisable, among other measures, for them to realign and remove political influences in order to prioritise the welfare of the nation.