Research Paper (postgraduate) from the year 2009 in the subject Health - Public Health, ( Atlantic International University ), language: English, abstract: A total of 750 blood samples were collected into the dipotassium - ethylene diaminetetra - aceticacid (EDTA) tubes and BD vacutainer tubes from the population of Porto Novo at random rangingfrom 2 years to 70 years of age. The ABO blood group systems were tested on the samples by theforward and reverse technique of blood grouping by tube method. A total of 320 individuals were shown to be blood group O (43%), the blood group A were shownto be 226 individuals (30%), blood group B were 167 people (22%) and blood AB finally were 37people making up to 5% of the population tested. This work follows almost the same discoverymade by other researchers of ABO grouping system and did not show a significant differencesamong the groups except in that reported on Brazilian Indians in Mato Grosso which registered100% blood group O among Indians of Mato Grosso by Bier at al(1982). The work serves as a fundamental screening on the distribution of ABO blood group system inPorto Novo and did not indicate whether there exists a difference of ABO blood group systemdistribution among other islands of Cape Verde and also a reference point for those engaged inclinical blood use like the red cross organisation and paramedical units who at times give blood onemergency basis.