A minilab is a small photographic developing and printing system or machine, as opposed to large centralized photo developing labs. Many retail stores use film or digital minilabs to provide on-site photo finishing services.

With the increase in popularity of digital photography, the demand for film development has decreased. This means that the larger labs capable of processing 30,000-40,000 films a day are going out of business, and more retailers are installing minilabs.

In Kodak and Agfa minilabs, films are processed using C41b chemistry and the paper is processed using RA-4. With these chemical processes, films can be ready for collection in as little as 20 minutes, depending on the machine capabilities and the operator.

A typical minilab consists of two machines, a film processor and a paper printer/processor. In some installations, these two components are integrated into a single machine. In addition, some digital minilabs are also equipped with photo-ordering kiosks.

Despite their small size, minilab machines may use chemical processing just like larger dedicated photo processing labs, using processes such as CP-49E or RA-4 for photographic paper processing, and C-41 for film processing. All necessary processing chemicals may arrive in a box (replenishment cartridge) containing enough bleach, developer and fixing agents to be mixed automatically for an estimated amount of paper, eliminating the need to manually handle and mix chemicals. Minilab machines were used in stores to perform film processing and printing in a short period of time, usually less than one hour from start of film development to the end of printing, partly because it eliminated the need to send rolls of film and printed photos to and from a large central photo processing lab.