This study evaluated the effects of five smoking processes on the contents of 10 major phenolic compounds in fillets of herring (Cuplea harengus), namely two traditional processes, involving smoke production by smouldering or friction, one process using liquid smoke atomisation, and two electrostatic smoking processes, also involving smouldering or friction. The effects of several parameters, such as smoking time, smokehouse temperature, electrode voltage, and fish fillet temperature before smoking were assessed for each process. The results indicate that the content of phenolic compounds are strongly affected by the process applied. The percentages of phenolic compounds in fish flesh remained constant and discriminant for a given process, regardless of the parameters studied, which implies that the smoking process used can be identified by determination of phenolic compounds in fish.