"I Feel Fine" is a song by the English rock band the Beatles that was released in November 1964 as the A-side of their eighth single.

[6] Lennon wrote the song's guitar riff while the Beatles were in the studio recording "Eight Days a Week" in October 1964, and kept playing it between takes.

[5] At the time of the song's recording, the Beatles, having mastered the studio basics, had begun to explore new sources of inspiration in noises previously eliminated as mistakes (such as electronic goofs, twisted tapes, and talkback).

Artists such as the Kinks and the Who had already used feedback live, but Lennon remained proud of the fact that the Beatles were perhaps the first group to deliberately put it on vinyl.

"I Feel Fine" is written in 44 time with drummer Ringo Starr's R&B-influenced beat (based on the "Latin" drumming in Ray Charles's hit "What'd I Say") featured through most of the song except for the bridge, which has a more conventional backbeat.

Just before the coda, Lennon's intro riff (or ostinato) is repeated with a bright sound by George Harrison on electric guitar (a Gretsch Tennessean).

[7] Public demand for the single was unprecedented, according to author Nicholas Schaffner, particularly in the US, where the market had been saturated with Beatles releases over the first seven months of 1964, "making the ensuing gap seem like forever".

[12] "I Feel Fine" reached the top of the UK charts on 12 December, displacing the Rolling Stones' "Little Red Rooster", and remained there for five weeks.

The song was the first of six Hot 100 number one chart-toppers in a row (not counting the EP 4 – by the Beatles) by one act, also a record at the time.

[16] As of December 2018, it was the 53rd-best-selling single of all time there – one of six Beatles songs included on the top sales rankings published by the UK's Official Charts Company.

[17] On 23 November 1965, the Beatles filmed two promotional clips for the song for inclusion in Top of the Pops' round-up of the year's biggest hits.

The mono version of the LP featured an exclusive mix of "I Feel Fine" with added reverb and a shorter fade as created by Beatles producer George Martin, which was also released as a single on Capitol.

[20] A radio show outtake in mono is included on the On Air – Live at the BBC Volume 2 compilation released in 2013.