ABSTRACT Background: Anaemia is a public health problem affecting millions of people globally, especially in low and middle-income countries. It leads to complications that affect patients' daily activities due to fatigue and impaired cognitive function. Objectives: To determine the prevalence and patterns of anaemia amongst patients attending tertiary health institutions. Materials and Methods: This was a retrospective study which used previous records obtained from the registers available at the Haematology Section of the Laboratory Complex, Chukwuemeka Odumegwu Ojukwu University Teaching Hospital, Amaku, Awka, Nigeria. These were records from 1st January 2016 to 31st December 2017. A proforma was used to collect data from the registers in the Haematology Department. Variables extracted were year, month, age, sex and patient's Department. Data were analysed using SPSS (Statistical Package for Social Science) version 20.0. Results were presented in tables. Results: A total of 4950 haemoglobin concentration test results were analysed. 2846 (57.5%) were females. The overall prevalence of anaemia regardless of the degree of severity was found to be 62.9%. Severe anaemia was highest in males 15 years and above (15%). Children below the age of 5 had the lowest prevalence of anaemia. (62.5%). Mild anaemia was highest in Children aged 12 to 14 (35.1%). Patients older than 15 years constituted over half of the data collected. Conclusion: The prevalence of anaemia based on available laboratory results is alarmingly high in Awka, Nigeria, when compared to other related studies within Nigeria and beyond.