A real-time loop-mediated isothermal amplification (LAMP) is described to diagnose cassava mosaic disease (CMD). The disease continues to cause great damage in Sub-Saharan African countries threatening food security. Early detection of the pathogen is paramount to control the spread of the disease and promote the safe exchange of clean planting material. Real-time LAMP in combination with a crude but rapid method of DNA extraction can be used to detect the two most widely distributed species of cassava mosaic geminiviruses in Sub-Saharan Africa, African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV), in less than 30 min at a single operation temperature (65 °C) without the need for any expensive instrumentation. Further, this protocol avoids the laborious extraction of high-quality DNA and making it suitable to be used in poorly resourced laboratories and in field settings.