Procedures for a.c. and d.c. polarography in anhydrous HF are reported. They are based on the use of a Teflon DME, an external Cu/CuF2 reference electrode and a sophisticated Kel-F vacuum system which allows a series of polarographic observations to be made on solutions varying widely in concentration of electroactive species and of supporting electrolytes without exposure to atmospheric moisture. In HF tin(II) exhibits two-electron waves both of oxidation and reduction. E1/2 values are reported for different media. The effects on reversibility and other polarographic characteristics of both electrode processes arising from varying both the fluoride concentration (using fluoroborate to provide constant ionic strength) and the water concentration are examined.