NMR studies of paramagnetic haemoproteins are reviewed with special emphasis on characterization of both structural and dynamic properties of haem active site. In the past decade, the development of NMR methodologies for detecting the connections between hyperfine shifted signals has contributed greatly to establishing systematic and reliable strategies for the signal assignments of paramagnetic haemoproteins. The use of reconstituted haemoprotein is a characteristic of the study of b-type haemoproteins and NMR studies on reconstituted myoglobins and haemoglobins are described in some detail. Additionally, nonequivalence in haem electronic structure between the two different subunits in human adult haemoglobin enables one to characterize the individual subunits in intact tetramers using NMR, and the advantages in studying tetrameric haemoglobin by N M R are also described.