Coulometry is an electrochemical method in which the amount or concentration of the investigated analyte is determined by measuring the electric charge required for a quantitative change in the oxidation state of the analyte in the coulometric cell. There is a difference in coulometry, which is performed with a controlled current or with a controlled potential of the working electrode. The coulometric analysis is based on Faraday's law of electrolysis, which speaks of the relationship between charge and quantity or mass of an electroactive substance. Devices for measuring the amount of charge are called coulometers (electronic current integrators). Potential-controlled coulometry is used to determine the number of electrons exchanged in an electrochemical reaction, measuring the amount of charge required to oxidize/reduce a certain amount of electroactive analyte in a cell, while current-controlled coulometry is used for coulometric titration and gives high measurement sensitivity. Therefore, the aim of this work is to define and describe coulometry as an electrochemical method, types of coulometry, device for measuring and application of the coulometric method.