The results of studies by Soviet and foreign specialists on the nature of propagation and prediction of abnormal formation pressures are summarized. The identification of zones of abnormally high (AHRP) and abnormally low (AHRP) pressures based on geophysics, geology, and drilling data is petrophysically justified. Sedimentation and determination of estimated parameters of complex oil and gas reservoirs occurring under abnormal pressure conditions have been considered using examples of various oil and gas bearing regions of the USSR.