This short book summarizes the results of serological analysis of weak Rh D antigen done by the author as a project during her BSc degree in Mount Kenya University Kenya. Commercially acquired monoclonal antibodies and anti human globulin were used in this analysis. Both micro titre and tube methods were employed during the analysis.The blood samples were sampled from the remains of the donations from the Regional Blood Transfusion Center (RBTC) Nairobi.The report includes the stages that were involved in the determination of the presence and absence of weak Rh D antigen on the donor red cells. The report also presents the discussion, outcome, conclusion and recommendation of the study.