:{{KW|FIELD}} [#]{{Parameter|fileNumber&}} {{Parameter|fieldWidth1%}} AS {{Parameter|variable1$}}[, {{Parameter|fieldWidthN%}} AS {{Parameter|variableN$}}]
* {{Parameter|fileNumber%}} is a file number used in the [[OPEN]] statement or a value from the [[FREEFILE]] function.
* Combined size of the {{Parameter|fieldWidth%}} parameters '''MUST not exceed''' the [[LEN]] = recordsize in the [[RANDOM]] [[OPEN]] statement or a [[ERROR Codes|"FIELD overflow" error]] will occur.
* Variables are limited to [[STRING]] types. Use [[TYPE]] instead of FIELD if you want to use numerical values.
* Once a FIELD is defined in a statement, [[GET]] can read and [[PUT]] can write data without placeholders or variables.
* [[LSET]], [[RSET]], [[PRINT (file statement)|PRINT #]], [[PRINT USING (file statement)|PRINT # USING]], and [[WRITE (file statement)|WRITE #]] can be used to place characters in the file buffer before a [[PUT]].
* All field definitions for a file are removed when the file is [[CLOSE|closed]] or [[RESET]] and all strings are set to null("").
* Do NOT re-assign a field defined variable value or use it in an [[INPUT]] statement if you want the variable to remain a field!