The article details how the technology behind LEDs (light emitting diodes) addresses the needs of architectural lighting. The authors contrast LEDs with the traditional metal-iodide light bulbs. Certain technical points should be considered when choosing an artificial light source: efficiency and long-life, colour temperature and chromatic resolution index (CRI) for guaranteeing superior performance of the light source in the chosen application. The technical parameters of the traditional light sources and LEDs, such as the colour temperature (in Kelvin, K), rated-life (in hours), and efficiency (in lm/W), are compared. The article emphasizes the disadvantages and negative aspects that should be taken into account when designing or employing LED technology, such as sensitivity to humidity and fluctuating electrical source, and especially, heat that is generated in the housing. The authors also discuss, however, the specific advantages of using LED technology for architectural lighting including instantaneous illumination, mechanical resistance to vibration, and low-level power source requirements.