Baling wire leads a strange double life. In one life, its original one, it is an essential part of agriculture and shipping. In the other, it forms part of the almost mystical duos of "duct tape and baling wire" and "spit and baling wire." In that company, it can be used to secure or repair (or even build) anything - if the need is great enough.

Baling wire is wire used to secure bales - originally, bales of hay or grain, but in today's industrial economy, anything that can be flattened and lumped into regular shape for transport or storage. Originally, baling wire was used manually - workers followed early mechanical reapers and secured the bales it produced by hand-tying wire around them, either on the reaper or on the ground. In the 1870s, the first automatic baling reaper was produced; also known as a baler. This handy agridevice would not only harvest product, but would also secure it into a bale automatically before producing the bale for collection or dropoff.

The first baler, invented by one Charles Withington in 1872, used wire to tie the finished bale. However, this caused severe problems; the machine would often drop broken-off bits of wire into the hay or grain it was baling due to its crude mechanisms and inconsistent wire quality. This led to livestock being injured by eating wire fragments, as well as to the loss of several grain mills to fire caused by sparks struck by the metal wire bits in the mill during grinding. As a result, the new automatic balers (sometimes called binders) were quickly changed over to use baling twine instead. The twine was harmless to both mills and livestock. Despite problems with the more complex mechanisms required to tie the twine (as opposed to simply twisting wire) the industry quickly settled on twine-based balers.

In the early 1900s, grain harvesters in the U.S. as well as the larger hay balers were available using either twine or wire, as new processes for making the wire (galvanizing and black annealing) as well as better quality control and manufacturing techniques allowed the use of wire without the risks of earlier systems. In addition, with the rise of standardized motor transport, packing balers began to show up, for use outside of crop harvesting; in these applications (cardboard boxes, scrap metal and wood, and the like) the use of wire was risk-free.

Wire saw a surge in the 1960s, as the newly-invented competing polypropylene fiber twine was destined to go through several revisions before working properly. It was harder to cut than sisal, domestic hemp or manila twine, requiring much more carefully maintained mechanisms; it originally did not contain ultraviolet inhibitors, which led to it becoming brittle and cracking when left in sunlight, and it was more prone to stretching as well as damage during movement. Eventually, these problems were mitigated if not overcome, and today, balers can be had that use either solution.

Modern baling wire, designed for use by machinery, is subject (like everything else!) to a standard. The current U.S. standard is ANSI/ASAE S229.6 FEB03, published by the ANSI and available through the ISO as well. It specifies the various dimensions, strengths, and processes for automatic baler wire, down to spool size. For example, the abstract for this spec states that:

This specification shall cover annealed baling wire for automatic balers. The wire shall be furnished in two sizes of coils: 960 m (3150 ft) minimum and 1981 m (6500 ft) minimum.