This book reported the literature survey of the chemistry of pyrido[1,2-a]pyrimidines. In this context, all the synthetic methods used for the preparation of pyrido[1,2-a]pyrimidines which considered as an important moiety in the field of organic synthesis, were reported. In addition, the biological activities and synthetic applications were discussed. The reactions of pyrido[1,2-a]pyrimidine compounds were reported. The type of its reactions include electrophilic (i.e. coupling, acetylation, alkylation, formylation, nitrosation and halogenations), condensation, ring transformation, ring opening, mannich reaction, aromatization and reduction. The reaction mechanisms were reported. The bibliography includes mainly 165 references.