Automated counters are used for generating hemogram reports and are more accurate than manual hemogram counts. They include 3 part differential counters (give differential of lymphocytes, neutrophils and mixed cell fraction) and 5 part differential counter (gives counts of lymphocytes, neutrophils, eosinophils, monocytes and basophils) and are superior to 3 part instruments in accuracy. The advantage of automated cell counters is that not only there are several routine parameters available in report format, but also many calculated extra parameters like RDW, and histograms, which would give added information to interpret. The chapter describes interpretation of WBC, RBC and platelet histograms. It also elaborates on the flags observed in WBC, RBC and platelets along with red cell indices as determined by the automated counter.