The objective of this study was proposed to evaluate the kinetics of silicon (Si)released insome Egyptian soils (sandy, calcareous and alluvial). The processes involved in the release of Si from soils during the extraction with 0.01F calcium chloride (CaCl₂) were investigated. A considerable amount of Si was released from most of the tested soil samples during the first hours of extraction and continued steadily until the end of the experiment (144 hrs). On average the total Si released for each soil group was 34.80, 93.78 and 62.35 mg kg^-1 soil in sandy, calcareous and alluvial soils respectively. The released Si was the least in sandy soils. Four mathematical models (parabolic diffusion, power function, and Elovich equation) were used to describe cumulative Si release. The Elovich equation proved that the Si release kinetics was satisfactory in the Egyptian soils.