Introduction: Nigeria had planned to introduce the rotavirus vaccine in the National Immunisation Programme in 2014, but this has yet to be done. Nigeria has the continent's highest mortality due to diarrhoeal diseases with little information on specific, prevalent genotypes. Aim: The study's main objectives were to identify the predominant rotavirus genotypes and examine the effects of existing local vaccination programs on prevailing rotavirus genotypes and on preventing rotavirus diarrhoea. Methodology: A one-year prospective descriptive study of children under 5 with acute diarrhoea was conducted from June 2018 to May 2019. Children with acute diarrhoea attending Asokoro District Hospital, Abuja. Children without diarrhoea were also recruited as a control group. Rotavirus ELISA and RNA extraction were done with commercially available kits, and positive samples were subjected to RT-PCR and electrophoresis to determine VP7 (G) and VP4 (P) genotypes. Results: Rotavirus-ELISA was positive among 231 (17.8%) children with diarrhoea and 29 (2.2%) of controls, with November, December. The predominant VP7 genotypes was G1 (n=116, 50.2%) followed by G9 (n=66, 28.5%). Viral Protein, VP4 (P) was mostly P [8] (n=143, 74.8%) followed by P [4] (n=21, 10.9%). The predominant genotype combinations found were G1 P [8] (n=108, 46.7%), G9 P [8] (n=62, 26.8%), and G2 P [4] (n=18, 7.7%). Very few mixed infections were found in the study, 2 (0.8%). Among 94 unvaccinated children with rotavirus isolates that were genotyped, G1 P [8] (n=88, 49.4%) and G9 P [8] (n=43, 24.1%) were predominant. Among 32 vaccinated children, G1 P [8] (n=13, 40.2%) and G9 P [8] (n=9, 28.1%) were predominant. Conclusion: The emergence of new genotypes such as G 12 P [4] found in this study emphasize the need for continued prospective monitoring of rotavirus at the molecular level to detect new threats to vaccine programs in future.