AbstractOne of the main characteristics of the Nigerian geodetic network is that it was observed or measured at different points in time starting from the early years of this century with instruments of varying precision. There is the need to improve the quality and strength of the network by re-observing selected lines and angles with modern and more precise instruments, incorporating additional measurements into the system and deleting some observations which do not contribute positively to the over-all accuracy of the network. The implementation of the above operations calls for the use of a sequential adjustment technique. The theory of such a procedure suitable for the recursive adjustment of the Nigerian geodetic network is presented.