The National Health Laboratory Service (NHLS) is the largest diagnostic pathology service in South Africa, with the responsibility of supporting the national and provincial health departments in the delivery of healthcare. The NHLS provides laboratory and related public health services to over 80% of the population through a national network of laboratories. Its specialised institutes include the National Institute for Communicable Diseases (NICD), the National Institute for Occupational Health (NIOH), and the South African Vaccine Producers (SAVP), as its subsidiary.

The NHLS is a public health laboratory service with laboratories in all nine provinces, employing approximately 7000 people. Its activities comprise of diagnostic laboratory services, research, teaching and training, and production of sera for anti-snake venom, reagents and media.