Following a general discussion of forensic serology and immunology, the characteristics of blood are described. Specific techniques of identifying bloodstains are then delineated for determining the presence of blood, identifying menstrual blood, and ascertaining the species of origin. Considerations for typing blood stains involve understanding the individualizing characteristics of blood and the application of bloodstain typing to casework. A survey of genetic marker systems is provided, according to which description and bloodstain typing is performed. Body fluid examination and typing concerns principally semen and saliva. The concluding discussion raises issues of collecting and handling evidence and of the forensic serologist as an expert witness. Tabular data and over 100 footnotes are provided.