In this review our recent research results on electrochemistry and electroanalysis of oxidants (e.g. hydrogen peroxide, ozone, hypochlorite and peracids) typically used as disinfectants will be introduced together with the related studies reported by other researchers. The electrochemical behavior of these oxidants largely depends on the electrode materials. At some electrodes an excellent separation of their redox peaks can be obtained and the results are utilized in the amperometric electroanalysis of these oxidants over a wide range of their concentrations. Further a simple novel method is given for a simultaneous potentiometric analysis of these oxidants using the iodide/iodine redox couple as a so-called potential buffer. Factors affecting the selectivity, sensitivity and response time are examined in detail.