Describes the principal mechanisms of red cell sedimentation rate in accordance with the available literature data. Characterizes the factors enhancing and inhibiting red cell sedimentation rate. Presents three methods for evaluation of red cell sedimentation rate: Panchenkov's micromethod, rapid method, and fractionated test. Discusses the most incident errors occurring in determination of red cell sedimentation rate and the clinico-diagnostic significance of this parameter in a number of diseases.