The Secure Digital, or SD, card was first developed in August of 1999. The creation of the SD card was made possible through a collaboration between Matsushita (which markets Panasonic brand products), Toshiba, and SanDisk. By working together, the companies hoped to create a next generation form of secure memory card. In addition, the companies hoped to put out a product that could successfully compete against the Memory Stick that Sony had released the previous year.

The companies hoped to create a small memory card, which they succeeded at doing with the SD card. The SD card measured only 24 mm x 32 mm x 2.1 mm. While this was amazingly small at the time, miniSD cards and microSD cards have since been released that are only a fraction of the size of the original SD card.

At the time when it was launched, the SD card was also considered to hold an impressive amount of memory for its size. In addition, it was compliant with the Secure Digital Music Initiative because of its copyright protection qualities. This is where the Secure part of its name comes from, as the companies were particularly careful about adding special encryption hardware in order to calm down concerns from the music industry that such cards would increase music piracy. Although the cards are theoretically capable of enforcing Digital rights management, this ability is not often utilized.

The symbol used to designate an SD card was not actually originally created for this new technology. Rather, Toshiba had created the symbol for its Super Density Disc that it had created as a prototype. This is why the D in the symbol looks like an optical disc. Many speculate that the companies decided to go ahead and use the symbol because of its connection with the music industry.

By 2000, the three companies announced that they were going to establish an industry-wide association that would set standards for the creation of SD cards. They also announced that they intended to promote the use of the cards for use in a wide range of digital applications, and they were quite successful. In fact, SD cards can be found in a number of gadgets, including digital cameras, camcorders, PDAs, mobile phones, digital audio players, DAB radios, the Nintendo Wii, GP2X, Global Positioning Systems, Multi-function displays in avionics, the PlayStation 3, and digital picture frames.