The review is devoted to a new method of sample preparation, solid-phase microextraction. Its advantages are miniaturization; considerable reduction or even complete elimination of the use of toxic solvents; high concentration factors; low cost; simplicity of coupling with instrumental methods of analysis; and possibility of automation. The main versions of solid-phase microextraction and the parameters of their optimization are considered, such as the chemical composition of the adsorbent, the thickness of the adsorbing coating, pH, the nature and concentration of the salting-out agent, extraction time, stirring intensity, temperature, desorption conditions, and analyte derivatization. Examples of using solid-phase microextraction in the analysis of environmental samples, biological samples, and foodstuffs are presented.