National anthems are solemn patriotic songs that are officially adopted by countries as the expression of their national identity which are rendered during special or official events. There are robust previous researches on the thematic and stylistics analysis of the just abandoned Nigerian national anthem without a comprehensive Linguistic and functional analysis of the old-new anthem. Therefore, this focus of this study is to investigate and present the functional analysis of the old-new anthem of Nigeria with a view to studying its experiential function and implications. Halliday’s Functional Grammar (FG) was adopted as framework for this study. Specifically, the theory of experiential metafunction: processes and transitivity. The data for this study is taken from the newly re-introduced Nigerian national anthem. Six process types were identified in the anthem: material, relational, mental, verbal, behavioral and existential processes. The findings of this work points to a predominant use of material processes to indicate the expected measures to be taken by citizens of Nigeria to strengthen the development and progress of their nation. Other process types are used sparingly to put in place relationships, and present the nation as important entity. This paper infers that the establishment of national unity is better portrayed through the functional analysis of the process types in the Nigeria Old-new national anthem because the linguistic tool of transitivity is that language form is not coincidental, but performs a communicative function.