An ADIF file is a data file saved in the Amateur Data Interchange Format (ADIF). It contains one or more log entries created by various ham radio software. ADIF files are saved in plain text and are used to exchange log information between amateur radio logging programs.

ADIF is used in the Amateur Radio Service, which consists of amateurs who use radio technology as a hobby. The format was released in 1996 and was adopted by a variety of Amateurfunk programs as the uniform format for exchanging logs between amateur radio enthusiasts. There are three specifications of ADIF. ADI files may be used by each specification of the format but ADX files (saved in an XML format) are primarily used by the third specification of ADIF. NOTE: ADIF files are more commonly saved as .ADI files.