Fender's early guitar design, known first as the "Broadcaster" and then as the Telecaster, was based on friend Merle Travis' design for a solidbody electric guitar, built for Travis by Paul Bigsby with a single row of tuners. Its bolt-on neck joint configuration allowed it to be produced on a much larger scale than the set-neck design of competitors, and it became an almost instant hit.

During this time, Fender also conceived an instrument that would prove to be essential to the evolution of popular music. Up until this time, bassists had been left to playing acoustically resonating double basses, also known as "upright basses". As the size of bands and orchestras grew, bassists found themselves increasingly fighting for volume and presence in the sound spectrum. Apart from their sonic disadvantages, double basses were also large, bulky, and difficult to transport. With the Precision Bass (or "P-Bass"), released in 1951, Leo Fender addressed both of these issues. Unlike double basses, the Telecaster-based Precision Bass was small and portable, and its solid body construction and four magnet, single coil electronic pickup allowed it to be amplified at higher volumes without the feedback issues normally associated with acoustic instruments. Along with the Precision Bass (so named because its fretted neck allowed bassists to play with "precision"), Fender introduced a bass amplifier, the Fender Bassman; a 45 watt amplifier with four 10" speakers. Neither were firsts; Audiovox had begun advertising an "electric bass fiddle" in mid 1930s catalogs, and Ampeg had introduced a 12 watt "Bassamp" in 1949, but the P-Bass and its accompanying amplifier were the first widely-produced of their kind, and arguably, the P-Bass remains one of the most popular basses in music today.

1960 saw the release of the Jazz Bass, a sleeker, updated bass with a slimmer neck, and offset waist body and two single coil pickups (as opposed to the Precision Bass and its split-humbucking pickup that had been introduced in 1957). Like it's predecessor, the Jazz Bass (or simply "J-Bass") was an instant hit and has remained popular to this day, and early models are highly sought after by collectors.